Hi, this is my first post in these forums. I'm an avionics software developer working on a CS Master's with no robotics background (beyond some Lego Logo and Mindstorms stuff way back when) but I'm looking to change that for my Thesis.
I'm looking at researching and developing a simulation environment for use in drone fleets (primarily UAV but I want it to be useful for ground and sea drones as well). While I want a reasonable basic physics handling of each unit my primary focus is going to be communications between multiple units of a BVR fleet.
Any suggestions on what I might want to consider or any research material I might find useful would be terriffic!
The competition held on March 20 and 21 in Taiwan. There are various events in the competition. Please refer to the official site : http://www.iaa.ncku.edu.tw/~whlai/uav/2010/
One of the events is Beyond-Vision-Range Flight. The airplane should fly far away and take some pictures of ground targets. The locations of tragets in the competition are shown in the following figure. The farest waypoint is about 3 km from home location.
We used EasyStar as the vehicle and UAV devBoard as the contorller. The plane crashed twice due to EMI problem before the successful flight. Because of the strong wind, it deviated from the expected flight path and disappered in the sky for about half an hour. When we were going to give up and the referee had asked the next team to take off, it suddently showed up above the home location. The crowd cheered as the plane safely landed on the runway.
Soon this platform will be ready and it's made for FPV / UAV flying for the amature marked.
Made of glassfiber.
Wingspan: 1,6 M
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I will update this page as soon I have more info..
[There was a bunch of very cool Tri/Quadcopter stuff on the RCG blogs today. Here's a sampling:]
Above: A very cool custom tricopter with a Trex body so you can tell which direction is forward. Check out the post for details on the pro quality pan-tilt camera mount.
And check this next one out. Did you know that you can make a Mikrocopter amphibious? This video is mindblowing. It starts underwater, but keep watching:
Finally, a "best of" video of Mikrocopters as camera platforms. How many Hollywood movies or TV shows have you seen recently that used quads rather than cranes?
Both of those quad videos are from this post, which is great introduction to Mikrocopters. Worth reading the whole thing.
Sparkfun created their own 3D model of their HQ for the Autonomous Vehicle Competition, which they've submitted to Google Earth. It's good, but I like our own Graham Dyer's version better (bellow). His has the Evil Trees!
1 horsepower = 7 pounds
I've come across this magic number using different sized rotors, props, and engines in large RC helicopters and planes, and also researching horsepower to lift divided by time in several ultralight and light sport aircraft and rotorcraft, and this is a good rule of thumb when developing something that needs to do more than hover or drift in the wind.
Guidelines for precise calculation of lift or thrust
http://www.heli-chair.com/aerodynamics_101.html
Comparison information using UAV specialist developer information
http://www.barnardmicrosystems.com/L3_engines.htm
Be sure to click on the different links for engine type (4 stroke, wankel, turbine, etc.) In fact, Barnard Microsystems is an excellent reference for those looking to DIY a larger drone, and is highly informative reading material in all aspects of UAVs.
Title says it all. Only 35 in stock and I just bought one to backup my original unit.
Regards,
TCIII
I've been busy writing the communication protocols between the Ground Station and Autopilot. I thought some people might be interested and possibly make use of the approach I've taken. It's all done in binary with discrete packets and makes use of DMA and Interrupts to use as little processor time as possible.
Asynchronous operation is achieved by the use of two FIFO queues and double buffered DMA channels for each radio. There is a lot of detail that will make the diagram above make a bit more sense.
Full article at: http://www.projectandromeda.com.au/blog
Had a few more flights with the ArduIMU yesterday.
I should mention, that with regards to RC flying, my main interest is competing in IMAC (Scale Aerobatics). Basically it's flying giant scale aircraft through predefined aerobatic patterns for judges. Last year I competed in intermediate (3rd of 5 difficulty levels) and this year I'll be moving up to Advanced (4th of 5 levels).
Arising from this interest, my long term goal would be to get an autopilot doing aerobatics.
Anyways, yesterday was the first flight of the spring with my contest aircraft, shown here.
After the first flight, to confirm that everything was still working, I couldn't help but put the ArduIMU/GPS on board for some data collection.
What I really wanted to know was if typical IMAC aerobatic manuevers could be detected by the sensors used on the IMU. If the sensors railed as soon as I departed level flight, then we might have to rethink things a little. On the second flight with the IMU on board, I put the plane through the Intermediate contest sequence from last year. By flying a known sequence it makes it easy to figure out what the aircraft was doing at each point of the flight, and to determine if the sensor data is appropriate.
The initial data analysis is favourable. I am using the ArduIMU code associated with the recent Ardupilot 2.5.1 work with a few tweaks to work with my equipment. I also added the gyro rate information to the ASCII data stream to give me a better idea of what's going on inside the ArduIMU.
Here are a couple of snapshots from the data:
The starting of the engine is clearly visible in the Roll Rate data. The engine is hand propped. A few flips with choke on to get it primed, and then a few flips with choke off and she's running:
You can see that the engine introduces alot of vibration noise into the rate gyros. I'm not too worried at this point because:
- I had the system hard mounted without much padding.
- I will be installing this in my smaller electric aircraft to start.
If I ever get cocky enough to Ardupilot a gas plane, I might have to add some filtering to the rate gyros to damp out this vibration.
The last maneuver in the sequence is a rolling circle. Basically, you need to fly a circle, while rolling the plane. You need to do 4 rolls in total, so after each 90 degree heading change the aircraft should have completed one more full roll. In my opinion, it's by far the most difficult maneuver they force us to do. Anyways, the data shows just how bad my "roller" is:
There's more stuff in there, but the fact that I can make sense of the outputs gives me hope that I can teach the Ardupilot to do the same :)
Thoughts, and To Do List:
1. GPS signal seems to go wonky as the aircraft rolls inverted (even for short periods). Still haven't decided if this is an issue, since during aerobatics, the attitude and attitude rate is more important than the lat/long. The key will be to make sure that the Attitude and Rate numbers aren't peturbed by momentary GPS jumps.
2. Definitely want to integrate the static airpressure system into the data record (I'm not sure I trust the GPS altitude numbers)
3. Add accelerometer data to the output stream. It would be intesting to see if I can track the gravity vector as I do a slow roll across the field.
4. Right now the data log is time stamped with the GPS Time of Week (TOW) value. Since the ArduIMU is spitting out sensor data faster than my GPS is updating the TOW, I'm ending up with multiple datapoints with the same time value. I think I will switch the timestamp source from TOW to "timeNow" (Arduino milliseconds since boot) to try to prevent this.
That's all for today. More to come.
Tom
I have been busily testing ArduPilot 2.5.1 with ArduIMU and correcting bugs in the basic functionality. I now have all MODEs working well in my primary airframe configuration and will now work on verifying other configurations (radio types, shield versions, thermopiles, etc.)
If you want to help test climb aboard. There is an active thread in the Forum.
