I've been lurking on this site for a while, and figure it was time to finally say hello.

My company builds small video-enabled mobile robots for education and research. Some of our robot controllers were ending up airborne, so I started looking more closely at customer requirements, and ended up designing a new controller that was more suitable for UAV applications.

We just got our first production batch of boards 3 weeks ago (see http://www.surveyor.com/blackfin ), and I'm in process of integrating them into 3 different airframes ...

The first is a prototype fixed wing flier by Ken Hill, the second is a quad rotor from AscTec in Germany that I'm working on in cooperation with a lab at MIT, and the third is a prototype scaled coaxial fixed rotor VTOL based on the Hiller Flying Platform.

The quad will probably be the first for successful control by the processor - it's definitely the most stable of the lot. However, all three projects are interesting.

By the way, I'm located in San Luis Obispo, California, in case there are other participants or lurkers here who are local and want a closer look at these projects.

Howard

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Howard,

Many thanks for the introduction, welcome, and congratulation on having a very cool job!

I've got loads of questions, but the first was as to whether the camera controller is also the autopilot on those vehicles. It wasn't quite clear from following those links.

Best,

Chris
Chris -

Yes - the camera controller will be the autopilot. Initially, I have just been using r/c to gain an understanding of flight characteristics of the various airframes and the Blackfin board is just hitching a ride and sending back compressed video frames via the wifi link.

The next step is to run the servo and throttle controls through the processor with commands coming via the wifi link - the java application (SRV1Console) that runs the mobile robots will be easily modified to provide the user interface, plus it has an archiving feature to capture the video. I expect to have this working with at least the quad in a week or so - this won't be complicated because the quad already has a serial interface and a very good IMU.

After that, things start to get interesting. My current plan is to first try to automate the takeoff and landing. With the VTOL, this isn't such a big deal - I just need a ground clearance sensor, and will probably use the Maxbotics ultrasonic rangers. This is a LOT more complicated with the fixed wing aircraft, but in a sufficiently controlled test environment, I might be able to combine the ground clearance data with onboard image processing to compute a horizon and gracefully bring the plane down.

If I get past the takeoff / landing phase, I plan to integrate GPS and add simple waypoint navigation. My main objective will be to combine position control with the takeoff / landing capability. If I can pull those pieces together, I will be very happy. Further on, there are many additional capabilities I can imagine, but I am focusing on this basic functionality for now.

Howard
Howard.

Very exciting! Keep us posted, and please open source your code--it will help sell your boards ;-)

Chris
Will do. And yes ... our code is already open source.
Chris -

Here's an update.

As mentioned before, we are working with new quad rotor called the "X-3D-BL Scientific" from Ascending Technologies GmbH in Stockdorf, Germany, with the concept of integrating the SRV-1 Blackfin camera and radio board with the UAV flight controls.

Interface is relatively simple - the X-3D-BL has a very capable onboard inertial measurement unit integrated with the brushless motor controls, so the interface between Blackfin and UAV is a simple 38kbps UART. To power the SRV-1 boards, we are connecting directly to the UAV battery pack (11.1V LiPoly).



We have mounted the radio board with a single standoff in place of the original X-3D FM antenna, after drilling a hole in the radio board and clearing a trace that goes to the unused Zigbee header. We added a simple antenna bracket, so everything is securely mounted.



We have made some simple indoor flight tests to verify that there are no issues with balance or radio interference. Image transmission through the WLAN from the SRV-1 Blackfin boards is working fine, and the UAV flight is very stable.



Next step is to run the flight controls from the SRV1Console (with some redefined buttons) through the Blackfin to the X-3D via the UART. One short-term goal is to capture video through the SRV1Console video archive function. After than, an ultrasonic ranging module will be added to the system for ground clearance measurement and control. Beyond that, we have a very long list of projects, including servo control of the camera tilt angle.

Howard
Howard,

Very impressive! Are you flying this in autonomous mode (GPS or synthetic GPS indoors) or is still RC controlled?

I hope you don't mind if I feature your post on the front page with a blog post....

Chris
Chris -

Control comes from a Java-based program called SRV1Console which connects the "base station" computer to the processor on the quad via an 802.11 WLAN. Video streams back from the processor on the same 802.11 connection. At the moment, there's an operator generating flight commands via SRV1Console, but autonomous control functions will be added. As mentioned above, the first function to be added will be altitude hold using ultrasound for ground sensing, followed by automated takeoff and landing.

I'm not certain yet what the sequence of development will be after that - clearly, we will be able to add GPS for outdoor waypoint navigation, but indoor navigation is a different challenge. MIT uses a really expensive 3D positioning system called Vicon, but there's a lot of research work in simultaneous localization and mapping (SLAM) using onboard cameras that should apply. We've done some relatively simple localization with the mobile robots that move in 2D, but extending the problem to 3D movement makes it a lot more complex (and interesting). The main focus will be to build a set of robot flier firmware functions that can enable development work on these challenges.

Feel free to feature the post - this is an interesting project.

Howard
Howard
Is this unit available for commercial use? I have noted on the X-3D-BL manual that these are for hobby purposes only and I am interested in purchasing one and converting it for commercial photography perhaps with GPS waypoint navigation etc. Also I saw on one of the videos about the X-3D that they were using an 8 rotor setup, clearly capable of a much greater payload. Do you know how this can be achieved?
I appreciate that we are covered by the CAA but I assume that the CAA and FAA will produce some regulations regarding the commercial use of these machines.
What is the 'X-3D-BL Scientific' and do you know if this is this available for commercial usage?
Steve
Steve -

The only restrictions I am aware of are described in the manual - "Our products are designed for the civil market only. It is strictly forbidden to use them in any military environment or to retail them to any military or military related organization. Using any of our components for larger scale flying objects is also not allowed." This would not seem to restrict commercial photography.

I think the X-3D controller is being used with a variety of airframes, as their forum (in German) is very active. The X-3D-BL Scientific is completely assembled, and includes the accelerometers, while it seems that the X-3D-BL is a kit. In any case, you could email team@asctec.de to get clarification.

This particular unit has a lot of power, though it would benefit from stiffer props if you planned to carry any weight. I have attached a technical paper which describes their design.

Howard
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Howard
Many thanks for that. I let you know how I get on :)
Steve
Hello there.

Stiffer props- Carbon Fiber

http://www.lcc-shop.de/index.htm


Dont know if thy prop will fit your machine.
I had not seen this LCC quad before - it looks pretty substantial, and the camera mount is nice. The price for a complete quad seems to be comparable to X-3D-BL

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