Hello guest, if you read this it means you are not registered. Click here to register in a few simple steps, you will enjoy all features of our Forum.
This forum uses cookies
This forum makes use of cookies to store your login information if you are registered, and your last visit if you are not. Cookies are small text documents stored on your computer; the cookies set by this forum can only be used on this website and pose no security risk. Cookies on this forum also track the specific topics you have read and when you last read them. Please confirm whether you accept or reject these cookies being set.

A cookie will be stored in your browser regardless of choice to prevent you being asked this question again. You will be able to change your cookie settings at any time using the link in the footer.

Thread Rating:
  • 0 Vote(s) - 0 Average
  • 1
  • 2
  • 3
  • 4
  • 5
QAV250 Guidance & Autonomy Testbed
#1
QAV250 GAT (Guidance and Autonomy Testbed)
[Image: zvawniT.jpg]

Parts list: 
Core electronics
  • FC: AUAV Pixracer / PX4 / QGroundControl
  • GPS: mRo GPS Neo-M8N+HMC5983 Compass 
  • Telemetry: 3DR 900MHz Telemetry radio
Power & Propulsion
  • Power Module: ACSP4 Power Module
  • Battery: Turnigy Nano-Tech 1500 mAh / 1300 mAh (1500 in picture)
  • Motor: EMax MT2204-2300kV
  • ESC: FVT Littlebee Pro
  • Props: Generic 5" props
FPV
  • Camera: Lumenier CS-600
  • VTx: ImmersionRC 600mW
Wiring Diagram:
[Image: Lc5RFhR.jpg]
Error in diagram: The ESCs depicted are UAVCAN ESCs (the Pixhawk community's take on digital ESCs / answer to DShot). However, they are not available at the moment, thus are not implemented in the final build

Inspiration for this build came from a post I saw on RC groups. It is impressive that the QAV250 can acquire GPS and telemetry capability that is common to larger guidance boats. However, I envisaged several improvements, which I implemented in my build
  1. Newer AUAV Pixracer replacing F4 Revo, whose guidance capabilities are underdeveloped after Openpilot dissolved
  2. Replace LEA-6H with Neo-M8N
  3. Adding FPV capability
[Image: AlLSqHr.jpg]
Side view, showing the jumble of wires connecting all the electronics

[Image: V7jxV87.jpg]
Top view, showing the telemetry radio and GPS competing for space with the VTx

[Image: 9UAs1TG.jpg]
Bottom View: Note the ACSP power module is directly soldered onto the PDB

Flight performance:
The GAT performed superbly in altitude lock, position lock, and RTH, with minimal drift. However, a waypoint mission was cut short due to LiPo sag. (I was flying in subzero temperatures) A second flight tested the vehicle's acro / racing capabilities. It is reasonably inferior to a dedicated racing build, not least because of the incomplete development of the Pixracer in this aspect.

Next targets: Full waypoint mission, publishing flight video and flight logs. 

To the community:
Is it pointless to equip mini-quads with guidance avionics ?
Is flashing a F4 Revo with ArduPilot / PX4 even possible as mentioned in the RCGroups post?
Anyone has experience flying Pixracer in a true racing built? How does one configure and tune such builds, and how do they perform?
Reply
Login to remove this ad | Register Here
#2
Quote:Is it pointless to equip mini-quads with guidance avionics ?
Is flashing a F4 Revo with ArduPilot / PX4 even possible as mentioned in the RCGroups post?
Anyone has experience flying Pixracer in a true racing built? How does one configure and tune such builds, and how do they perform?

It's unusual to do so, first of all space is an issue, normally you want your GPS to be placed far away from the rest of your electronics to avoid interference. Secondly mini quad isn't great when it comes to flight time so it doesn't far enough to need GPS most of the times. But IMO it's a good platform to test/learn GPS flying on, it's cheaper and relatively safer...

I am not familiar with Arduiplot or PX$, as far as I know Ardupilot is based on 8-bit processors? not sure if they have been ported to STM32 chips already, hope someone can answer that for you.
Don't be a LOS'er, be an FPV'er :)  My Gear - Facebook - Instagram - Twitter
Reply
#3
Personally looked into the "Flashing ArduPilot to Revolution" issue a bit. Apparently, it is a project dating way back to the OpenPilot days, and its actual name is "ArduPilot32", github here: https://github.com/scenkov/ardurevo. I could test it myself, but I've flashed RF on my Revolution and I am having trouble reverting back to LibrePilot at the moment.

OpenPilot / LibrePilot offered a "GPS-assist" mode that could get the best of both worlds between Acro-Racing / GPS, but again their development is dead. The CF-led configurators are negligent on GPS development, which is for good reason, but I can't help but be disappointed. Thus I turn to Pixracer and PX4.
Reply
#4
This is like what my Cheap250 build evolved into. I am using it to learn about the flying aspects (it's my first quad) but also enjoying the GPS implementation and guidance type features. I figured it was cheaper and easier on a small quad than building something bigger.

It's not common, and tuning has been interesting because the users of APM/Pixhawk generally fly bigger stuff, so the advice for the frame is mismatched against the advice for the flight controller tuning.

Either way the build is nice and I think doing full-on guidance on a small frame is the "the future"
Builds: Mini-Quad  -  Tricopter 
A Blog

Reply
#5
Thanks for the encouragement, Aaron!! Smile

I agree that weight and space is a very significant issue with miniquads. Basic GPS modes such as position hold and RTH does not require much modification to a quad since they only require a single GPS module (~10 grams). 

However, for the quad to become a true guidance boat that can do waypoint missions, two way telemetry is absolutely necessary. The combined weight of the whole suite of electronics require more compromises to be made.

I flew heavy guidance boats based on Pixhawk before, so I can become obsessed with GPS guidance Smile
Reply
#6
If you take a look at the Hobbyking site they have some nice stackable 35x35 PDB/BEC boards with APM/Pix compatible power metering as well. That will help control one size aspect. The match OSD/Telemetry board doesn't have much output power though so not really much good for your application I think.
Builds: Mini-Quad  -  Tricopter 
A Blog

Reply


Possibly Related Threads...
Thread Author Replies Views Last Post
  1st QAV250 build help HotaruT 9 683 19-Aug-2021, 04:54 PM
Last Post: HotaruT
  Help Need guidance attaching R-xsr receiver to TBS oblivion BigBeard 17 5,649 05-Mar-2020, 06:28 PM
Last Post: BigBeard
  Build QAV250 with 16mm standoffs beatbox 0 458 16-Dec-2018, 11:12 AM
Last Post: beatbox
  Help racerstar 20 amp 4 en 1 rv44 1 553 10-Sep-2018, 01:03 AM
Last Post: RENOV8R
  Discussion Qav250 or SparrowR4 Alex 2 1,384 08-Mar-2016, 11:45 AM
Last Post: Alex


Login to remove this ad | Register Here