Results tagged “Amir” from Amir Guindehi's Blog

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.

I'm sorry it took so long to write my next blog entry, but we were quite busy debugging our UAVPs and fixing problems.

But let's start at the beginning. As you all know we had 2 big problems. First, we had to set the yaw integral to zero and second the whole UAVP had a tendency to flip.

After long investigations with sepcially hacked debug firmware (written by Wolfgang) we finally could isolate the flip problem. It turned out to be quite simple... Since the motors never should stop, we had a sort of lowest level of thrust we allow the motors. Now if the UAVP needs to stabilize it speeds up one motor and slows down a second. Should it happen, that the motor slowing down reaches the minimum allowed speed, we keep it at that and do not allow it to go lower.

BUT, the second motor speeding up we allowed to go faster! This resulted in a inbalance which in turn escalated to flipping the UAVP!

Fixing this was simple... if we have to limit the motor slowing down, we also limit the motor going faster. Wolfgang implemented this simple fix and the UAVP does not flip anymore.

I still ponder if this is the best solution. Imagine a "dynamic throttle adjustment" which will increase the throttle as soon as the motor slowing down crosses the limit. Increasing the throttle would increase the spinning of all motors allowing the motor slowing down to be able to do so!

I think I will try to implement this solution sometime.... I made a enhancement ticket on our new UAVP development server dev.uavp.ch.

Small sidenote: You can reach the new UAVP development server under all the UAVP domains dev.uavp.de, dev.uavp.at, dev.uavp.ch and dev.opensourcequadrocopter.de

The second problem concerning the compass could be fixed quite easily as well. Wolfgang had used a fixed constant value of 16 to correlate the compass's and the yaw-integral's influence. Reduncing this value to 8 or 6 corrected the problem. So it really was a sort of fight between yaw-integral and compass. Wolfgang made this value configurable.

But back to the last test flights. Using the newest firmware (a pre-3.13 version) my brother was able to fly for as long as 6 minutes, which is one of our longest flights.

But watch for youself:

We hope to fix the last problems soon. Then nothing will hold us back from flying up to 20 minutes with our 5000mAh batteries. And there are as big as 8000mAh batteries available out there. I think the weight will be no problems on ou overpowered UAVPs...

We completed the last flights for today. I can say, we are back in the air!

Setting the gier integral value to zero worked wonder! Everything is back to normal and as long as you do not make too great movements with the sticks everything works fine.

It seems that the new software version 3.12 has problems with large stick movements so I switched on the "Specky-Bit" which reduces nick and roll signal to half the normal maximum.

Today I was able to complete my testflights without loosing a propeller!

Now watch my newest testflights:

As you can see it's stable enough again to try some outdoor flights. Sadly the weather seems to play bad and we hope to be able to fly outside to the end of the week.

Now that our UAVP fly again, eventually we can try to work on the software. I have several ideas I would like to try to implement. Attitude stabilization, coordinate translations using the compass, throttle adjustments and special throttle courves, GPS support, it all should be possible...

Today we continued our testflights. We still want to eliminate the periodic movement we have on the gier acis. We tested a lot of different parameters, bigger and smaller integregrals as well as no dampening by setting the differential values to zero.

It all seemed to no avail. We had that periodic movement all the time exept when we started perfectly so that no gier correction seems neccessary. As soon as some movements on the gier axis starts the periodic movement never ends again.

Strangly my brother does not experience this problem through he experiences another problem which I have as well. Suddenly without cause the whole UAVP flips or extremelt starts correcting in one of the nick or roll axis. This most often results in a crash or even a broken propeller.

We taped my tests again. You will see our testflights with the 3.12 software using different integrals and no differential. Later on we raised the differential parameter as well in the hope to dampen the periodic movement. In the last scene I rolled back to the 3.11 software to see if the periodic movement exist there as well but as you can see on the movie, it does not exist in the 3.11 software which let's us guess that the problem has something to do with the compass support which 3.12 introduces.

Interesting is that my brother is able to fly 3.12 without a periodic movement on gier, but on the other hand, his gier seems not to be very stable and we saw turn arounds of 180 degrees!

This where my testflights:

Later on we powered up my brother's UAVP and did further tests. It seems that the perodic movement of the gier axis can be eliminated by setting the integral value of the gear closed-loop control to zero.

More tests showed that even a value of one in the gier integral will result in small periodic movements.

Following we show yoy the later testflights my brother did. They were quite successful as you can see! Setting the gier integral to zero seems like a very good idea at the moment!

I think this movie shows quite good that the new setting with the gier integral value of zero is at least a good fix for the moment to counter the priodic movement problem.

The testflights from yesterday clearly showed the need for parameter tuning. So we dedicated today purely to finding the best parameters.

The be short, we failed. After much testing and tuning we can say, that we did not find the best parameters and even have more problems than yesterday.

Yesterday we noted that our gier was periodically swinging. So we tried to fix this today and had to notice that as soon as the gier integral gets a bit bigger the periodic swinging starts. Even when we configured a differential part of 80. Only reducing the integral part to -3 ot -5 helped and even then we had a small periodic movement on our gier.

Furthermore we now have a aperiodic tremble on nick and roll. We tried to compensate with a bit of differential and less proportional, but we could not eliminate it fully.

It seems our parameter tuning turned out to be a bad idea. On the whole the UAVP flies less stable than yesterday and we do not know why.

The problems started with the upgrade to the version 3.12 of the software. It's clear that the changes in the software required changes in the parameter (compass support & differences in P & D calculations of the closed-loop control). But up to now we could not find really perfect parameters.

Here come some movies of our testing today.

First we show you the flip my brother got today. We do not really know what caused it:

Next I show you some of my testflights. If you watch carefully, you see the tremble on nick and gier as well as the periodic movement on gier:

The result of my last flight was another broken propeller...

We will ponder the results of today tests and the try to fix the parameter debacle.
Expect more to follow...

Today the newest testflights have take place! I have to raport that our piloting skills are growing from non existant to the point of being quite miserable...

My brother was the first starting today and he was partly successful. His start was a bit shaky but when he got into the air he stayed there for a little while. Aproaching the trees he looses orientation and starts to correct into the wrong direction crashing streight into the bushes:

Then the problem arose how to recover the UAVP. It seemed lost in quite dense bushes which my brother didn't seem to mind and rushed trough them searching for the missing UAVP. In a short period of time he found it and brought it back:

After this my brother was out of the game for now and my time began...

I started my UAVP quite good and was able to hoover for some time in front of me. Then the UAVP aproached me a bit too much and I tried to stear against. This resulted in such a big changing angle that I automatically panic like an amateur and counter-steered even more in the other direction. It seems I steered a bit too much...

... the results were 1.5 loops and a defty crash:

After this I was out of the game and my brother who meanwhile recovered and fixed his dented UAVP took over. This time his flight was much more controled. He was in the air for a long time and finally landed when his battery run out:

The conclusions are that the new version 3.12 of the Wolferl software definitivly behaves different that the version before. The changes in the paramter P and D resulted in a very different flight behavior and will result in much parameter changing for us.

We both definitivly need more differential on the gier axis (it's oscilating!) and I surly need to lower the integral part of nick and roll, I don't want such a fast reaction to my flight control failures. And furthermore we both want to lower the proportional values of nick and roll too.

We will tune our settings and try out more in the days to come!
Expect more of the story here in my blog.

As you all know we are ready for the first test flights.

We want to keep you posted, so we thought we would not let you miss our latest experiences even trough they were not that successful and even a bit embarrassing. It seems piloting an airship is not such an easy endeavor for untrained guys like us, even trough the closed-loop control stabilizes and helps a lot! Things like mass, velocity and inertia keep you quite busy piloting an UAVP...

Sunday was a bad day for us test pilots... We went to the football training ground which we elected as ideal start place. On the way there we had to notice that there was quite a bit of wind (later that night a small storm hit our area). Silly us we decided to fly anyway...

First, Taarek tried to fly and crashed when he bounced on the ground and his antenna touched his rotor. If you listen carefully you hear the "click" when the antenna hits the rotor and gets cut in half:

Later on I tried my own luck and went into the air with my own UAVP. I was no more successful than my brother and crashed after 22 seconds:

Something went terribly wrong. When I touched the ground you hear the beeper start and then my motors stop and it crashes. It seems as if I lost my battery or my receiver when I crashed. having switched it off and on everything is fine again. I can not yet really explain what happened.

Next we will upgrade our UAVP software to version 3.12 which will support the compass. This will make sure the UAVP's orientation will be stable all the time, since the compass is a reference sensor with no integral error.

Be sure to hear more about our next flights in my next blog entry!

It flies! It flies!

But let's start at the beginning...

After having built our UAVP as described in my last article, today we fixed the last problems and did the first testflights indoors!

Everything went well after we fixed some bad soldering on Taarek's board and after having found out that one of the sensors of my own board was not sitting streight.

We made a small movie showing Taarek's UAVP flying in my living room:

Then finally, when it was nearly dark, we went out for the first outdoor testflight! There was barly enough light to make some camara pictures and so we failed to put the first outdoor flight on movie tape... :(

But to give you an insight in what went on, take a look at these outdoor pictures!

My own UAVP stands ready for it's first integral outdoor flight:

And up it went! As you can see it really flies:

And it can gain height quite fast, I was astonished myself:

And here you see Taarek's UAVP standing ready for it's first real outdoor testflight:

And it jumped into the air as well:

Then we needed to change our location since it was too dark for unexperienced pilots like us. We went up to the street, where there's some light from the street lamps.

Taarek successfully completed several flights near the street in front of the next building:

These first testflights were very successfull and showed the considerable potential of these UAVP constructs!

We were astonished about their ability to gain height within a very short time and about their considerable agility in the air. They are so agile that we even feared several times to crash accidentally against trees, buildings and the like, just because we could not assess how fast the UAVPs change direction, height or orientation.

Be sure to hear more about our next flights in my next blog entry!

As the honored reader probably already knows we finished flight controller and frame. For those new to the story I must mention that in my last two blog entries I talked about the construction of the flight controller and then described how we built our frames.

Our UAVPs already started to resemble quadcopters.

So next we started mounting the four brushless motor controllers which we intended to use. Both UAVPs will use YGE30 brushless motor controllers which are able to handle current up to 30A and should be fast enough for a quadcopter with 54cm diameter.

This will allow us to use a wide range of motors:

We added the flight controller in the middle of the frame and we put some Klett bands under the frame to be able to attach the Lithium ion polymer battery pack we intend to use:

When all connectors and power cable were connected it looked like this:

The second UAVP looks similar:

Next we started pondering the problem of crashes and how to protect the fragile flight controller from impact forces.

To be sure to have the electrics protected all the time we designed a sort of cap for it which surely will absorb some of the impact should it happen to fall on it:

Looking at it on the second UAVP it shows how tightly everything fits:

Mounting the Lithium ion polymer battery pack did not take long.

Finally ready to for flight we connected the serial connection to our laptop and started to tune the flight controller's parameters for it's PID closed-loop controls:

Here is another detail picture:

The second UAVP with mounted Lithium ion polymer battery pack looks similar:

With this we finally finished the construction of our two UAVPs. All pre-flight checks check out and it seems the two quadcopters are fully functional and ready for flight.

The new frames and flight controllers will have to prove themselfes in their first flights. I will tell you more about success or failure of our test flights in my next blog entry!

As I told you in my last blog, we successfully finished two fully functional Wolferl flight-controller boards for our future UAVPs:

Next we wanted to build two stable and strong frames for our quadrocopters.

We bought several four cornered aluminium poles which we used to build a aluminium cross by milling notches into the middle of the poles so that they fit seemlessly. We then secured them in their place by scews and small aluminium plates which we drilled holes into accordingly.

We built two different frame types, one built from solid aluminium poles and one built from hallow aluminium poles.

The hallow variation has a weight of 232g and looked like this:

The solid cross weights 524g and looks not really different:

As you can see the weight difference is nearly 300g so we decided to use the hallow version for our first try on a frame.

Next we drilled holes for the motor anchorage and mounted the motors:

One of the two UAVPs will use Hacker 20-20L motors with EPP 1045 propellers which will give it a thrust of over 600g per rotor. This will result in a total thrust of over 2.4kg for all four of them. Our expected total weight will be around 1kg so we will have some 1.4kg thrust in reserve:

The second one uses AXI 2217/20 motors and looked like this at that stage:

It's motors will do also around 600g thrust per motor with the same total thrust of 2.4kg:

With mounted EPP 1045 propellers the Hacker version looked like this:

Next we unmounted all motors again and started building some landing gear for the quadcopters:

In the end we went for a simple contuction which will also help absorbing some of the deformation energies of hard landings:

When we combined the frame and the landing gear it finally started to resemble something like a quadcopter:

This will serve as a frame for our future UAVPs.

The next step to completion will be adding all the powerlines and mounting the flight-controller in the middle of the construct.

I will tell you more in my next blog entry!

In the beginning it all started with a visit to CCC's 23C3 Congress end of last year where we saw a Microdrone in action. I wrote about that visit and our exceitment about the advances in closed-loop control in this blog entry.

Following the visit to 22C3 we discovered the comercial product X-UFO and bougth one immediately:

Later on we discovered the UAV Community on the network. Several Open Source projects have been very successful in creating their own version of a Universal Aerial Video Platform. Most notable are Wolfgang's UAVP , Holger's MikroKopter and last but not least the Paparazzi Project.

After long forum inquest and even longer discussions with my brother we decided to join the fun.

At first, we did not have any parts to build something, so we started simple by playing with the main processor of the UAVP Board. The board implements the flight stablilization closed-loop control using a PIC microprocessor, which I put on my experimental board to play with:

To be able to work professionaly on the project we cleaned up my workplace and prepared everything. Note the nice digital storage oszilosope I own now... :)

We got the first parts for our own UAVP two weeks ago from several german shops:

Over time all the other parts except for the frames were finally delivered and we started the construction of our own UAVPs.

It seems that the frame producer has big troubles delivering in time, so we decided to build our own frames. We still hope to receive the ordered frames sometime in the future. This makes sense, since we want to build several UAVPs and for that we need more than one frame...

We then started to work on the flight controller board. It's all implemented using SMD, so everything is quite small and complicated to hold and place:

Two days (and nights) later, we finished the two boards finally convinced that we burned most of the parts to hell and that the two boards will never work as expected:

But who would have belived it?

One of the boards worked perfectly immediatley, the second one we got to work after finding one badly soldered pin. This is near perfection!

Normally such SMD boards get made with a method called reflow soldering, which is something we can't do easily at home. I have to mention that this is not a complicated SMD board to solder for an experienced person, but to us doing this for the first time it was a real challange!

It looked adventurous when we checked out the boards:

The small green plates you see at horizontal and vertical angles on the board are the sensor breakout boards used by the flight-controller to stabilize the horizontal position of the flying UAVP.

So we finally got two working flight controller boards for our future UAVPs.

There's still the question of a frame to use and how to build it...
... but I will tell you more of our Quest in my next blog entry soon to follow!