Recently in UAVP Category

I have to tell you hot news: Yesterday a picture of my UAVP got printed in the press!

Prof. Dr.-Ing. Heinrich Warmers of the HS Bremen invited to a QC convention in Bremen. He asked me if I could provide a good UAVP picture for an article in the local press covering the QC convention. I offered him all my archives including the pictures from the QC convention in Regenstauf and by chance he choose a nice picture of my UAVP.

But see for yourself:

As you can read in the text we did not get mentioned even trough Heinrich told the authors that it's a UAVP. On the other hand the Paparazzi project was mentioned, which is another open source project implementing QC favored by Heinrich and his team.

We finally came round to dig through our pictures made at the Quadrocopter convention in Regenstauf.

My brother and I joined the Quadrocopter convention in Germany on Saturday around midday after having driven 450km to Regenstauf, a village near Regensburg. At first we visited Cadmium's lab, where we meet Wolfgang and a lot other folk of the QC szene. Later that day, around 18:00, we went to a sports hall where everybody sent his QC into the the air.

As you can see on the photos, a lot of different projects and different UFO designs joined the convention. It was great fun to see them all flying!

Direct Link to the album: UAVP - Treffen Regenstauf

The convention in Regstauf was really great stuff and every km we had to drive was worth it!

We did some more test flights with our cam onboard our UAVP. I think we did some good air pictures and I wouldn't let you miss these!

Again we mounted a Canon Powershot S50 directly under the UAVP. It had no servo support or anything and was turned by 45 degrees so that the landing gear wasn't showing on the picture as before. I talked about this in my last blog entry.

I've explored Picasa (the Google thingy) a bit and this is a first test of placing the pictures on the picasa webserver.

Let's see how this works out:

Direct Link to the album: UAVP - Second In-Flight Pictures

Another movie I would like to show you is our first near-night flight while making a small movie.

We started in with the last light and then flew until our batteries were empty. In the end it's really dark and one can observe our 3x 3W Luxeon LEDs in full colors... :)

I'm sorry that you did not hear from me for such a long time!

It was holliday time so I went diving in the Red See on a dive safari and was quite busy the rest of the summer. Today I finally found a little bit of time to write a new blog article. Expect some more blogs about my hollidays and a nice collection of underwater pictures and movies soon!

Yesterday we took a cam into the air for the first time! The pictures are not really spectacular but I thought I should not let you miss them.

We mounted a Canon Powershot S50 directly under the UAVP. It had no servo support or anything and was turned by 45 degrees so that the landing gear wasn't showing on the picture. The whole cam we mounted in a box of styropor and attached that to the backside of my UAVP.

The cam was switched to series-pictures and we blocked the cam's trigger button.

But take a look for yourself: The first aerial pictures

One of the better pictures is this one:

We could even shoot a pictures of ourselfes while flying:

Later on we dismounted the cam and did some flights in the half dark. After we finished the first battery we mounted a new one and wanted to start again. I don't know what I thought but since my flight timer was not set to zero because of the first flight, I wanted to reset it.

For that I simply switched of the remote control! What a big mistake.

I already had switched my UAVP into flight mode and so, when I switched off the remote control the UAVP lost RC connection! The receiver switched to fail-mode and switched the throttle channel to hoover-power (another bad idea of mine which I corrected now)...

But watch for yourself what happend:

I was lucky... :) Nothing really bad happened!

I broke two screws and I had to replace the antenna, which came into one of the propellers.
Everything is already fixed again... :)

This weekend we had wonderful weather and we were out for more testflights. Sadly we soon discovered that my brother's UAVP had a hardware problem. He was able to start but soon after starting his UAVP suddenly nicked into one direction and crashed.

We could reproduce this several time as you can see in the short video below and each time the same happened. We think it could be another unclean soldering pad.

But watch for yourself how Taarek's UAVP crashed:

After this unsatisfying result we fetched my UAVP and tried again.

This time the hard work showed!

My UAVP flew way better than any time before. Using the new throttle curve I was able to hoover, nearly fly a full circle (I paniced in the end :}) and I even flew out over the feld and back. It was absolutly amazing how much it gained from the new throttle curve.

I've plotted the new throttle curve and you can see it here:

The new throttle curve doesn't sound so angry like the one before. Compared to the throttle curve Wolfgang implemented in Trunk it still allows optimal hoovering at around 50% and it still allows to reach the maximum throttle by using a steeper gradient in the end which exactly reaches the maximum all the time. The new throttle curve has a parameter L which allows to lower or elevate the curve for different motors while still keeping the input maximum at the maxium output.

After the movie session I took another round and flew until my 5000mAh and my 2500mAh batteries were empty. It was great!

Furthermore I have to mention that I started on my new "fixcoordinate" branch. It will try to decouple nick and roll from yaw and would allow to fly differently.

Imagine flying into one direction while yawing all the while around your own yaw axis? Or a fly-by while the copter turnes to keep one side directly orientated towards another object?

If this sound interesting to you, read my enhancement ticket on dev.uavp.ch. It describes the idea in detail.

Ah, and last but not least:

Are you interested in helping us?
Would you like to become an UAVP Developer?

If so, check out the page How To Become UAVP Developer on dev.uavp.ch!

As I wrote in my last blog we got our IOGEAR Class 1 Bluetooth Serial Adaptors. Cracking the case was easy and within minutes the bare board lay before us.

At first we paired it with our PC and got a COM43 as our Bluetooth COM port. We then first tested the adapter with the power supply and our proven RS232 cable. We were able to receive the startup message of the UAVP but we were not able to send characters to it at first.

A short investigation showed that the adaptor needs RTS and CTS connected to be able to send characters to a device. So we soldered a new SUB-D-9 plug with RTS and CTS connected. Using this plug the connection worked perfectly and we were able to control the command line of the UAVP via Bluetooth!

In detail it looks like this:

Sadly UAVPSet, the great configuration software Thorsten wrote for us, only shows COM1 to COM9 and seems not to be able to use COM43. I wrote Thorsten about this and I hope he will be able to fix this. It would be very cool to be able to flash via Bluetooth!

Later on we mounted the adaptor (back in his case) to the UAVP:

We also expect a lot of knowledge from debugging information captured while flying via Bluetooth!

We finally came round to hack the Wolferl software. As promised in ticket #7 we implemented a throttle curve for UAVPs with overpowered motors like ours.

The implementation was streight forward and when we finally realized that IGas does not get reset on each cycle but only when the RC interface receives a new value the hack was done within minutes. Tuning the throttle curve graph took a while longer.

This is what we came up with:

Implementation of the above throttle curve took place in revisions r170 and r171 in the subversion repository.

A short test and debugging session followed. During that time we plottet the IGas input and output values to see how our new throttle curve is behaving.

As you can see the new curve starts steeper (while we did not yet reach flight velocity) and a while (at 75) before we reach flight velocitoy (which is around 110-120) the new throttle curve starts to have a gradient of 1/2. This allows for a lot smoother control of the motors.

When we finally came round to a real flight test of the new patch we found out, that we were very successfull! Flying our overpowered motors has become a lot easier as you can see in the following short movie which we made while testing:

We are pondering now, if we shall extend the throttle curve to a more general form where 3 different grantends and one free location of gradient change can be choosen or if the orginal solution is fine enough for everybody like it is.

We will see... further tests will follow.

Last but not least I need to tell you of my newest gadget. It's a Class 1 Bluetooth Serial Adaptor from IOGEAR. I've already cracked the housing and made some pictures of it.

This is the top:

and the downside:

It should be a able to do Bluetooth to RS232 forwarding up to 100m. We will see if it does it as promised. I found one problem. It's powered by a 6V/0.3A power supply. I need to find a way to generate that power on-board.

There will surly be a way... :)

Yesterday we re-soldered everything on our two boards. After having seen sudden changes in behavior, perfect first flights and terrible second ones, we decided to have a closer look at our soldering on the board.

Further inspection discovered several unclean soldering pads which we corrected.

And guess what happened today? Our UAVPs flew perfectly and without these erratic changes in behavior! We were both able to fly our 5000mAh batteries to the end!

Now, before I write down too much, have a look yourself at our testflights of today!

The first movie shows my brothers flight. Something went amiss with the FLV encoding, so I would propose to download the WMV file... it of better quality anyway!

In the second movie you can see the testflight of my own UAVP. As you can see it flys a lot more stable and controlled than the last few times! It seems that a lot of the problems we had have their cause in unclean soldering.

My newest testflight was very successful if one ignores the unclean landing at the end...

I think both our UAVP are now stable enough to start playing with the software. As you can see in the enhancement ticket queue on dev.uavp.ch I have several ideas I would like to try out and eventually merge to the main trunk, if the implementation gets stable enough.