Projects

octopilot

OctopilotAboutOctopilot is an open source, modular autopilot for radio controlled planes. It can be enabled/disabled through an extra channel/switch on your transmitter, and when switched on, stabilizes the plane and navigates it back to the starting location, where it will circle. It can also ... [More] optionally trigger external actions, like taking a photo or dropping an item, when it reaches a waypoint. Soon I plan to add the ability to enter a set of waypoints for it to navigate to one by one. I also plan to begin making use of data from the proximity sensor to allow octopilot to land a plane at a specific location. There are other fun additions coming soon too, like stabilization of inverted flight, and an on-board TV-out to use as a text overlay onto a first person point of view video feed. Octopilot's modular and configurable design already allows for a large amount of flexibility. So for example, you can use just navigation, or just stabilization. The numbers of receiver channels and servos are configurable. Servos can be reversed. Either one or two channels can be used for ailerons. TV-out can be turned on or off, and much more. More Photos NewsSunday, June 14th, 2009 It's been a long time since my last round of test flights. Real Life has been busy, and I've been living on different continents from my octopilot rig. But I'm back in town for a couple weeks, and trying to get in some testing while I can! Today's test flight went great! Now that I'm using real PID controllers to manage pitch and roll, and have had a chance to tune the related constants, the stabilization is much more responsive, and no longer seems to have problems with oscillation. Tuesday, December 9th, 2008 First Test Flight was (mostly) a success! I was mentally prepared to watch the plane fly itself off into the bay. But happily the hardware and the switching between manual and autopilot felt totally solid. The stabilization worked fairly well -- pretty good for a first flight. When I switched the autopilot on during a dive/roll, it would stabilize itself! However, it was overcorrecting and sometimes oscillating. When flying with high throttle, this was especially noticeable. I think some real oscillation damping logic is in order. Navigation sadly was a no-go, as the GPS couldn't see satellites through the plane's foam body. I've moved the GPS antenna to the top of the plane, just behind the wing, and it now locks quickly. I look forward to test flight #2! StatusThe first prototype is now installed in a Multiplex Minimag. It is flyable, and successfully stabilizes flight in most cases. It seems like the Kalman Filter code might be getting a bit confused when the plane rotates in multiple axes at once. This may be a limitation of multiple axis Kalman Filtering. I may need to switch to a true 6DOF sensor, and a propeller implementation of this code. I still need to tune some constants related to navigation, to make sure the plane doesn't over-steer. See more info on the Status page. HardwareOctopilot is based on the Parallax Propeller microcontroller. The Propeller is quite a powerful little microcontroller, rinning each of its 8 cores at 80 mHz. This works out great for communicating simultaneously with all the peripherals in this project. I'm using the PropStickUSB as my Propeller of choice for this project because of its tiny form factor. I'm using the EM406A GPS module from Spark Fun for navigation. I use the 5-Degrees-Of-Freedom Inertia Measurement Unit from Spark Fun for stabilization. I also added this wide-beam Ultrasonic Range Finder LV-EZ0 which I plan to use for obstacle avoidance and/or elevator calibration. Any RC plane radio transmitter and receiver combination with at least 5 channels should work fine for this project. I use the Spektrum DX7 transmitter and the Spektrum AR6100 receiver. Here's a more detailed Parts List Links and ThanksOctopilot draws code and ideas from other projects, including Paul Hubner's PNav Autopilot Perry James Mole's GPS Routines (from PNav) Jason Wood's Kalman Filtered IMU Matteo Borri's Dynamic Math Lib Beau Schwabe's Servo32 Thanks also to Heraldo for taking the photos. Other RC LinksHow to add a video camera to your plane for $20 How to use a spare LP5DSM transmitter as a buddy box [Less]