Hi RC people,
I have built my first ever drone and had gone through a maiden flight, result was a crash land. I’m pretty sure that the base parameters needs some serious fine tunings and tweaking, suiting my drone. My drone should possess smooth maneuver, stable Altitude hold & Loitering and RTL during fail safe – these are my expectations and I request your suggestions from your experiences and knowledge.
Suggestions and advice are requested: 1. What kind of tuning is required for smooth maneuver, stable Altitude hold & Loitering and RTL?
2. How do I start with the tuning process and what to be tuned?
3. Is any pre-set values to be revisited initially, before tuning?
4. Is indoor tuning with strings, help ? (
https://diydrones.com/forum/topics/arducopter-tuning-guide)
5. Will Autotune be helpful for smooth flights, what needs to be done before performing auto tune ?
6. Also sharing any feedback/ advice/ personnel experience can help me to improve myself ?
Drone Configuration:• Purpose: Photography
• Frame type: X- Frame – Quadcopter
• Frame size: 680mm
• GVW: 2.8kgs (Drone + 4K camera)
• Motor: EMAX MT3110 700Kv
• ESC: EMAX BLHeli 25Amps
• Propeller: 1238 CF propeller
• Battery: ZOP 14.8V 4500mAh 45C Lipo
• FC: APM 2.8 + Ublox M8N GPS + 3dr Power module
• Firmware: Arducopter V 3.2.1 (Last update for APM 2.8 board)
• Radio: FrSky TH9X – 8 Channel
• Telemetry: 3dr 100mW Telemetry – 433mHz
First Maiden Flight: I had the drone out for a maiden flight with the existing PIDs and the default parameters in the APM 2.8. I had setup only Stabilize mode in all the 6 flight mode options, since I’m not sure how the drone responds to the other modes. And most importantly, I wanted to see the drone’s performance in Stablize mode.
It was a mid noon in an open residential plot, the wind was very mild and I had the take-off. The drone lifted-off from the ground at nearly 60% of the throttle. But the wind was carrying away the drone. Since, I was in Stabilize mode – I tried to keep the drone in position. But the drone responded too aggressive to my roll and pitch sticks. I somehow tried to land the drone, coz I do not want to loose it in the wind. I lowered the throttle stick very slowly, but it happened to be a crash land and my propeller got damaged. Then, it was time for the propeller change and I decided to tweak the base parameter (PID gains, Pitch/ Roll tilt angles and any other required fine tuning) before taking them up in the air.
Changes done to the base parameters:ANGLE_MAX (cDeg): Default value=4500 ; New Value=1000 ; Comments:Difference in tilt angles observed - 10deg
ACRO_YAW_P: Default Value=4.5 ; New Value=1 ; Comments:Now the Yaw rate is smoother and not aggressive as was in default values
Background on the Quad build: (I’ve put this session at last, since I do not want to bore anyone with bla.. bla.. stuffs in the first)I am Arunkumar from Chennai, I am a Mechanical engineer by passion and an Engine calibration engineer by profession. I am so much fascinated to build a drone rite from my college days, but never found time and budget. Its been almost 5 years after graduation now and I decided to pursue it. I started surfing on the web regarding building a drone by late 2018 and almost touched upon every basic topics. And finally came up with my requirement for building a drone, I wanted to see how things look from above. Yeah, I decided to build a drone with capability of carrying a camera payload of 0.5kg or atleast an action cam with Gimbal.
I decided to build an Quadcopter and started to begin with the GVW calculations, with the help of 3D CAD modelling (Calculation part in the next paragraph). I liked the design of Tarot-680 and Alien H4 680, mainly their looks and portability. I wanted the drone to be very portable and have space to mount the camera equipment. I started looking deep into Alien H4 680/ DAYA H4 680 designs and modelled a 3D CAD respecting the basic symmetrical rule for X-frame, i.e. when the axis of the motor mounts are joined by lines, looks like a square whose diagonal length measures 680mm.
I finally built a 3D model of my frame after multiple iterations, which respects both symmetrical rule and fold-ability. I wanted my complete frame to be made out of Carbon Fibre (CF), but considering the availability of CF here in India – I decided to go with Glass Fibre (GF) for the base plate, CF tubes for the foldable arms, aluminium motor mounts, TAROT mounting clamps for the CF tube and a wider landing skids. Since I had the complete 3D model, I was able to specify the density of each material (CF, GF and Al) and could finally get a very closer estimate of my frame weight (~700 grams). Believe me, my drone now weighs the same as the estimated weight. I felt this is quite heavier for a frame along with landing skids, but this was due to the high density of Glass fibre and the M3 Carbon Steel bolts (nearly 40 numbers).
Then proceeded to look for the available Flight Controllers (FC) in the market. Researched on that topic, finally decided to go with APM 2.8. Because, I liked that had a open source platform, compatible for other types of RC vehicles and mainly the budget. Further looked upon for the type of Motor – Propeller – ESC – Battery combinations, considering their own weight that adds to the GVW and matching the thrust provided by the combination. After many iterations, my calculated GVW of my drone was 2.3 kgs without camera.
GVW: Drone = 2.3kgs | Drone + Action Cam = 2.3 + 0.2 = 2.5kgs | Drone + 4K Camera = 2.3 + 0.5 = 2.8kgs
I decided to have my thrust to weight to be 2:1, which is the thumb rule. I chose EMAX MT3110 700kV motor which provides a maximum thrust of 1.4kgs @ 17.3Amps in combination with 14V battery and 1238 CF propeller. The total thrust provided by the motors shall be 1.4kgs x 4 = 5.6kgs, this shall be an exact match considering the critical GVW=2.8kgs (i.e. Drone + 4K Camera = 2.8kgs).
Then, I started procuring the materials and components required for the build (both from India and China). Out of which 90% of the electronics were procured from Aliexpress and the building materials from India. It took almost 6 months for me to collect all the components. Finally my drone configuration was supposed to be as below;
Now, once after collecting all the components, I started to fabricate the frame first, next the wirings, setting up the motor configurations. Fabrication and wiring were one of the very trickiest part in building the drone, my personnel opinion. Because even a single wrong solder can ruin the complete setup. I referred to the “Flight Setup” from the Ardupilot website
https://ardupilot.org/copter/index.html and after few reworks, I finally built the complete drone. Yet, the calibration part was left out.
I started referring to the below tutorials for each;
Radio TX/ RX Setup:
TX/RX – Flight mode switch setup:
https://www.flitetest.com/articles/Turnigy_9x_and_Arducopter_flight_mode_setupESC Calibration:
APM Setup: All the 8 parts of Painless 360 channel
Firmware uploading, Compass Calibration, Accelerometer Calibration, Radio calibration, Fail Safe setup and other Mandatory calibrations were done. Successfully !!!
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