Some pictures to start...
Thought some of you may be interested in this build as I intend to build an aircraft capable of 1 hour flights to map large areas in order to Create some Digital Elevation models for GIS mapping purposes. Initially i will be doing this for experimental purposes. I know there are a lot of rules and regulations in around commercial photography etc.
I will be focusing on the following
I know this is a highly specialized area, but i do have some of the above from asking various people on here (initially posted about this in my blog area, but that was wrong place, so posting here...)
Right where to start...
I have selected the Ursus Airframe for this build as it seems to have a large wing and space for enough batteries to give slow, stable flight for up to an hour or more in some cases. It has been talked about on here before
Material: EPP and wood
I'll try and post more pictures than words.. .as they are more interesting to look at...
Airframe arrived, fuselage part assembled,
Wooden spas glued into wings, Glass rods glued into tail booms
Fuselage glued together, with, wooden wing joiners glued into place
Wings joined, APM arrived, sticker stuck to horizontal stab.
After a few weeks of tinkering, my APM2 has arrived, And with much help from Chris and Michael I have managed to get HIL mode running pretty well in Xplane 10. I have been familiarising myself with the MissionPlanner as much as possible. Learning how the PID settings work.
Servos implemented, Undercarriage on.
I have also been playing with the Canon CHDK (Canon Hack Development Kit) on an ixus 80 and Intervalometer. Which is how i will be taking the photos from the plane, I wanted to see how long it can take pics for before the battery dies, I took pictures every 120seconds, and it took 81. Review was selected though after each picture, And i will be taking pics quicker than that. I created a time lapse from the window. Not that interesting, but its all part of the learning curve.
I have upgraded the nose wheel undercarriage to a more robust strut with steering as well. This should give plenty of ground clearance for the Camera Gimbal
Testing the placement of the electronics, need to decide where to put the APM2, R149DP Futaba RX and the Camera IMU. Plenty of room in here for 2 x 5000 3s lipos! AUW is currently 2.7kg!
A few questions for all you apm2 users...
Whilst the weather in the UK is unflyable (for me!). I am going to attempt to solder the connectors onto my APM airspeed sensor pitot kit and 3dr radios. Having never done any micro soldering before I was wondering if the soldering equipment I have is upto the job...
Here's a snap of the iron, solder, and pitot board i need to solder... The iron has a minimum temp of 150 degrees C. not sure soldering iron tip size, or if its good enough, These are what i've bought
Is there a best technique to soldering these components together? The 3DR Radios and pitot came with no instructions...
Next Question, What is the maximum wind the APM2 and Skywalker combination will fly in with no pitot tube? Is it a sensible idea to fly in 13mph wind with no pitot?
You may have sorted this out by now but..
It looks like a good temp as you are just soldering the header pins onto the pcb. Doublecheck the entry of the shorter pins. I mention this because I have made the mistake of not paying attention and soldered the long pins in. (This happens only once, usually). The pins could be soldered on either side but take care to ensure the connecting cable is oriented correctly if you 'mirror' the pins for a different mechanical situation.
The pins will take most of the heat. The assumption here is that if you have such a nice setup, you have been soldering for a while. I posted a pic of my power distribution pcb in THIS thread if you need a reference.
The initial photos are of a poor soldering job. My pic is down the thread.
When soldering these low pin count headers, sometimes I use a small drop of cyanoacrylate at the ends of the pcb, NOT in the holes, to ensure the plastic tree is flush to the pcb. Nothing is more annoying to me than crooked header pins.
Cheers for the Info RD, I am not an experienced soldering person. Attempting now!
First attempted waypoint navigation flight with the Skywalker and APM2 - complete success!
Weather was perfect (clear and wind was < 8mph) so thought i'd bite the bullet, and disconnect the APM2 from the Sim and install into the Skywalker - Did 3 relatively short flights and the plane followed the waypoints perfectly. Couldnt get the ESC to engage in Auto mode, possibly because i need to reverse the throttle channel in APM Planner config. So did the flights with a constant 50% throttle. The plane banked pretty sharpish in the turns, but was amazing to watch...
Heres a short video with no sound of launch, then flicking to auto, and showing plane flying to waypoint 1 in the other direction. The APM flies the plane wonderfully! can't wait to plan a larger more interesting route! and i'll strap a camera on as well..
I think this is going to be perfect for camera runs to ensure i can photograph a decent sized area with overlap.
Skywalker mapping test with APM2 flight control. After lots of umming and arring, I decided to hand over all flight control surfaces and throttle to the APM2 in the skywalker.
the plan is below, together with a downsized version of the photomosaic. I simply installed the camera in the wing of the skywalker on two bits of foam tape and some hook and loop to secure it in. I also added some ripstop tape on top to ensure it didn't fall out (this was a mistake, it killed the dampening and gave motor vibration blue)
I am relatively happy with the results, whilst the stitching is off, ICE did a good job of trying to stitch poor quality photos at different angles.
The flight path - 400ft, lines 70metres apart
Camera: Ixus 80, ISO Auto, Shutter speed 1/500, focus infinity, photo every second
The results...(downsized to 4000px accross)
continue fixing the URSUS so i can have a roll controlled gimbal internally as designed above. seems the roll gimbal is essential from my tests.
Nice work! I am basically doing the same thing with a Bixler..
Can you share the flight track? I am curious about the stability of your plane.
Here is the flight track kmz file, i am not that happy with the accuracy, i was doing the flights across wind, but may try doing them at a different angle next time...
The flight path looks very similar to mine (attached) using my Skywalker.
The must be some way of improving these. I have tried to avoid having 2 waypoints close together but with not much success.
Hi Jerry, just had a look at your flightpath, I agree, they are very similar, I reckon we need to add more points in between the main end points to ensure the aircraft stays on track, I think the secret to this is ensuring the plane hits the waypoint first time, instead of having to go back and try again, it seems you may need to up the crosstrack gain, based on your flight path, its late here, i'm off now, but will study your flightpath in greater detail tomorrow and get back to you...ideally it would be good if they could follow the path exactly....
I can only apologise for living on the other side of the planet.
Many thanks for your comments. It does get lonely sometimes.
I would have thought that fewer waypoints would be better but given my results I am open to any suggestions. No rush.
Hi Jerry, I have been studying/comparing our two flight path files, they both seem to have the same inherent characteristics, IE. Not following the lines at all! - As you are using a skywalker, if we are both using the same PID setup config files, on a fairly windless day, we should be getting the same, or at least similar results,
I think the Default waypoint radius is 30, It seems any lower than this and the plane doesn't hit it first time, hence the circles near the waypoints. For my next flight I am going to increase the crosstrack gain, as it seems there is no crosstrack correction going on.
I would have though the setup file for the skywalker would be spot on.
Another thought, I know you need to be flying at a constant 12metres per second to get the best out of APM2. I am not currently using an airspeed sensor, this could be the problem.
If anyone else is reading this, could mine or Jerries flight path accuracy be improved? is anyone getting more accurate flights with a standard skywalker and no pitot tube?
Thanks Richard. It would be nice to get hold of a more refined parameter file.
We will wait and see.