Goal: Autonomous / semi-autonomous aerial mapping for creating georectified orthogonal imagery and eventually digital surface/elevation/terrain models (DEM, DTM). I'm in preliminary stages... though I believe that my POC is proven and so currently in testing and then on to my intended pilot project.
Current aircraft platform for testing and learning (and crashing):
Bixler 2 -stock setup plus flaps
- This plane can handle a lot of weight IMO for its size and stock motor etc. You absolutely have to get your CG squared away when you load it up but once you do it really soars and the ability to fly slow while stable is critical for mapping needs.
- Here's what I have on board when fully loaded:
- APM 2.5
- Ublox GPS
- 3DR 90Mhz transceiver
- RC rx
- 800mw vtx with rubber duck antenna
- Sony camera - in heavy metal housing (FPV)
- Turnigy 2200 Mah lipo
- RMRC 1100Mah lipo for vtx
- canon point and shoot
- A lot of hot glue from busting apart the fuse on crashes early on (prior to putting all the gear above on board)
- Plenty of duct tape and packaging tape to protect against future (inevitable) crashes.
Turnigy 9x 2.4Ghz stock - 9 channel tx 8 channel rx (was affordable alternative for me)
- I have the flaps controlled by one of the knobs instead of 3 pos switch I used to use because I needed it for APM flight mode control (described below)
- Currently have 4 switchable APM flight modes configured via tx Gear switch as master and F.mode - 3 position toggle as slave. The gear switch is essentially an on/off between manual and all auto modes. This way I can switch to any one of the 3 position modes directly from manual and back to manual with one flip of switch if in trouble. This has so far been a nice set up. These are my 4 programed modes
Autopilot / Stabilization: APM 2.5
- In a bunch of bench tests and just a few field tests it seems to be performing consistently...
- Stabilize mode is absolutely wonderful. Landing in this mode is all but autonomous. You just line up your orientation and bring the throttle down, and you can pretty much watch it land, maybe an elevator nudge at the end to make it glide across the ground.
- This is a fantastic feature and combining this with FPV for mapping linear features has a lot of potential, especially if you have a downward looking video feed.
- Autopilot mode with loaded waypoints is obviously the key for my entire project. So far I have one successful mission flying to 2 waypoints. I had to take manual control again before the plane started for home because people started arriving at the field and I was not willing to test with people below. Next test I will run another simple mission and complete the return to home and loiter. I will also set more variety in my WP altitudes.
- RTL mode appears to be working well also. I need to test various altitudes to get it where I will want it for most applications but so far it seems to be doing its job.
3DR 900Mhz transceivers- so far great range, no problems
- For real-time data from the plane, this is amazing.
- You can also update your mission from the ground by adding WPs, or simply load the next mission.
- I could see this being useful if mission locations are adjacent to each other and within a reasonable range. After completing the first mission you could switch to loiter mode and while loitering, upload the next mission. Then just switch to auto mode again and it should begin its second mission and then return to home. If there's ample battery life and you want to save time from coming in for a landing and relaunching for mission 2, this could be a great approach. I will test this at some point...after I finish my other hundreds of tests. lol
1280 Mhz 800mw vtx with 12db pad antenna and multi channel vrx (all from readymaderc)
- Still testing - getting interference but working on it...
GCS: Mission Planner
- Great interface to integrate map view, HUD and even FPV. The HUD is slick looking and it has a nice base of data but you can add a whole slew of overlays as well. I prefer the least screen clutter possible.
- I use easycap to feed live video from vrx to my laptop and overlay the live HUD coming in from the 3DR telemetry transceivers.
- It looks good and really no noticeable delay
- Still having trouble recording the video feed consistently. 90% of the time I get an unusable cropped video...still sorting this one out
- Also, can't seem to play video back in any video software. I upload to youtube just to see it...it's a pain.
Please let me know if you have any questions or tips for me.
I would like to learn from others here as I am a total novice.