A while ago Mr Mel mentioned autopilot systems, at the time I was having enough trouble flying at the best of time without teaching a machine to fly so I didn’t give the idea much time, but more recently I have looked into this.
The first system that I discovered instructions on was the Arduino system, which appears to be a very extensible modular system which appears to allow you to fit together various modules and sensors to build pretty much anything you want (http://en.wikipedia.org/wiki/Arduino). This seemed great, but looked like it would need a lot of time and effort to get a simple system working. Carrying on looking I found some proprietary systems which had proprietary price tags. Eventually I came across the arudpilot system which appears to be a nicely packaged and programmed autopilot system based on the arduino systems, and it wasn’t that expensive. So I purchased a ardupilot, GPS with compass and an OSD module for the telemetry and for about £50 or so everything was delivered.
The Mission planner software which is used to program the ardupilot is rather impressive, but also a bit daunting at first view.
once connected to the ardupilot it starts receiving telemetry information. So I need to start with the basics, I’ll move onto full mission planning when I’ve managed to get the basics working.
The ardupilot hardware will work as an autopilot for planes, cars, helicopters and various configurations of multi-copters. The first step was to install the Ardupilot firmware onto the device so that it has the basic information that will allow it to fly a plane. The next step is to hook it up to the radio and the planes control systems
The ardupilot has a split power system with the input and the output power separated in this way:
Since the bec on the Catalina’s ESCs was probably 3amp at the very most I decided to use a second bec. I know the ESCs will power all the servos, so this is connected to the output line and powers all the control surfaces, and I connected another 3amp bec to the radio which provides power for the radio and ardupilot, both connect to the same battery using a 2 to 1 XT60 connector.
I powered up the system and configured the radio top and bottom points as per these instructions: http://plane.ardupilot.com/wiki/arduplane-setup/first-time-apm-setup/ I setup a mix on the gear switch and the flaps which combined gave 6 positions for the flight mode control. These I have setup with the options, Manual, Stabilize, Fly By Wire A, Loiter, Return to Launch, and mode 6 appears to be locked to manual as the systems ‘failsafe’ option.
Finally I hooked up the mavlink telemetry to my FPV gear and checked the information that gives on the screen:
As you can see its quite a lot, I think I will have to try to reduce the amount of information shown on this screen as soon as I can get hold of the appropriate cable and configuration software.
So the next step will be to test fly it…
Unfortunately my ground station for some reason did not record. I did get higher resolution shots from the on board camera, but this didn’t give the telemetry. I am really disappointed by this, and will update this post as soon as I can get some ground station recording done.
Loiter was engaged at 1:26, Return to launch appears to be engaged at about 2:05. The plane seemed to be heading rather far over the house and away so I bottled it and disengaged it and went back to manual at 2:37 back to loiter at 4:18 I think, then off and back to manual at 5:00. Then a bit of a bouncy landing.
Mr Scott also followed the catalina with his Riot, but because I didn’t know quite how the ardupilot would perform I did fly rather high which made following it a challenge. Also as with all the videos the low autumn sun plays havoc with the camera trying to expose the recording correctly
At 49 seconds return to launch was engaged, the plane then flew itself until 2 minutes and then manual for a better landing.
Really happy with the way it worked, would have been happier if I had some telemetry recording from the ground station to know more about what was going on, but will get this next time. Once I have a bit more GPS information recorded I can also move onto full mission planning, setting waypoints, and ultimately takeoff and landing 🙂
Although it is very stuttery, here is the onboard with the on screen telemetry, I think the stuttering is because there is so much more on the screen, so the compression on the recorder is so much more difficult and the recorder isn’t great. But it gives a good idea of what happens when each of the modes are engaged.
Working from the top left downward is:
Air speed, Ground speed (I dont have an air speed sensor so not sure if this is accurate), Throttle, battery percent (battery sensor not connected), Climb rate, GPS satellites in view, current and battery voltage (again battery sensor not contected), Longitude and Latitude. Middle column shows Roll angle, home direction arrow, warning text, artificial horizon, RSSI (looks like a bomb, but is not connected) and telemetry heartbeat at the bottom. Right hand column shows, home distance, home altitude, current altitude, stopwatch, windspeed (linked to the air and ground speed, not sure how accurate this is, looks about right for today), pitch angle, WP distance and direction (don’t know), current flight mode (manual, loiter, return to launch0 with current heading to the right of this, and the heading rose under this.
A slightly better onboard video
But an Awful landing!