Our H1 drone was finally ready to be tested with new detachable landing gear, 3-axis gimbal and the Gopro camera (powered by an extra 3S-lipo battery). The objective of the test was to test the flight modes (mainly altitude control and position control) via 3DR telemetry connection to an Android phone and the Tower app. It was quite noticeable that the quad needs alot more power to overcome in-ground effects at take-off. This is mainly due to the mass balance with the camera at the nose of the airframe. The altitude control mode worked quite well even at low elevation of 3-4 metres. Unfortunately, at low-battery voltage an automated landing doesn't occur and this resulted in hard-landing (more like a hard crash!). This piece of software will have to be investigated. The manual operation of the Gopro is a bit cumbersome. The alternative of using the WIFI link to operate the camera was investigated but was not deemed a good idea given the potential inteference...

When will I fly again? I've been asking that question for a while now. After that expensive and silly mistake of loosing my Blade 300 CFX to some uncalibrated mass balancing, the wind of excitement was whiffed out of my spirit. I must say, this has allowed me to refocus my energies on the helicopter simulation model and how it should be modeled such that the research of the neural network algorithms could be easily prototyped and embedded into an autopilot software suite for HILS and flight testing. I must say, I feel like I've made quite a bit of progress on this front. Even though my spirit is itching to get something flying in the sky, the notion that I'm getting closer to creating a simulation environment where these algorithms can be tested, explored and refined for flight testing. I'm also grateful that during this time, my company has agreed to fund my research and I now the ability to procure the items that I need to properly get this research off the grou...

So the time had come for me to test the gopro on the Heli and answer a couple of questions. One that was answered quite quickly was how stable was the configuration. It turned out to be quite stable after all. Although attaching the camera at the nose of airframe makes contro in windy weather quite intricate. I had a couple of close shaves. The eventual footage didn't produce much desired results although that was expected as not much thinking what into the vibration isolation of the video camera. The maiden flight was to see if everything will work as expected. One could potential use a vibration removal video editor although that it last resort. Accumulated flight time: 94min

So I've decidex to try out something I've been meaning to try out for a while now. Which is to setup my Gopro camera for some aerial photography. Eventhough I've been looking at getting a more polished system like a Dji Phantom drone, I thought there's a lot of mileage I can get just using what I already have. So having studied the best layout for the camera and battery, once the weather clears out, I'll be trying out this system. I'll need to get a Fatshark system to get into proper FPV flying although the aim is not for that at all.  The mass of the Gopro with casing is about 140g with means the all up weight has increased by 26% which means less battery life although one would not need 4min of video anyway. 

It's been a while (over three weeks to be exact) since I've flown the heli. I must say I was quite nervous at first knowing that it's the first few minutes of flying after a long time that are quite critical. I also acquired a headset for my gopro which also worked quite well. But none of that mattered because many headaches have taught me to not have a big head in things that I'm still learning. So only after the third battery did I start with Nose-in maneuvers and a bit of slow circuits. Now that the holidays are upon us (and I still don't have a carry case), I will have to repeat this flight when I come back. I was tempted to take it with so I can get some nice shots of nature and the sea side. But I realised that I can't afford to loose this airframe as when I come back the instrumentation of the IMU will begin. Accumulated flight time: 84 min

Great flying yesterday at the park next to our house. Conditions are again just right to do some circuits and brief nose-in hover. I must say I feel that that I'm really enjoying the heli alot better now that I have tweaked the thrust curve. It remains responsive and quite stable around hover. Started using my homemade cap mounted gopro. The videos look great. Visit here to see some of them. It's nice and stable and after a while, you forget that you have it on you. Accumulated flight: 79min

So decided to try and get some flight time at a park near my house. The calm weather had it that I managed to do more nose-in hover and slow circuits. All in all, I will need to make another landing gear as the plastic material is too brittle to hand hard landings.  Accumulated time: 64 min

So today was a really good day because I've managed to hit just under 15min of flight using the three batteries show in the picture and most importantly with a failure. The wind was alot calmer today which made flying a breeze (excuse the pun). I was also able to do nose in and slow circuits which was a huge confidence builder. Now on to the specifics: Even though I was doing tail control (and to be fair there's a pretty bandwidth gyro in the loop as well), I found that rotating the heli to get it into a nose in position caused quite a drift away from me so much so that I had to quickly bring to tail-in in order to recover the heli (achieved about two succesful crash-worthy recoveries - Yeah!). This could potentially be a inherent in the dynamics (which i think it is) or there's further tuning that's required. In any case, success once again. I can see why accumulating more flight time in bulk helps. You get to correct and improve that crucial confidence onto th...

So today was a day when I decided to increase my flight time per session. I've started using two battery packs which meant that I know have to change over and also do some tweaking/learning on the transmitter to have a more comfortable flight. Even though It was quite windy (which is pretty normal now), I find myself being quite nervous still, Although It will go away with time. It could also be that I know how powerful this heli is and that I'm really wary about doing too much too quickly. To my credit, the heli got away from to about 50m and 15m in height and almost freaked out. Luckily I didn't panic and slowly brought the heli back in eventhough I was really struggling to make out its orientation. I was tempted to run closer but I must say I froze a little bit. I realize the amount of wind pushed it away and I wasn't actively controlling the throttle on the heli. Now I know better. I decided to have a couple of landings (some of them really hard) s...

Another succesful 4:30 min of tail-in and side to side hover flight. Accumulated time: 21min. I found it quite difficult with wind to stay at a consistent height, I landed the heli twice and I should have made changes to the throttle/pitch curve or the mixing. It was quite challenging flight in hover in gusty conditions but I'm finding keeping the heli in the air longer much easier. Next is to slowly transition into face in and then nose in (although I feel I'm more comfortable nose-in). In the meantime, I've started working a instrumentation platform that will be integrated between the landing gear and the frame of the heli to hard gathering data. That should bring about more result-orientated fun!

So after the crash from the previous flight, I received a new set of landing gear. Given that I was on daddy duty this weekend, I didn't get to do any flying. So today during lunch I decided to get over my fears and get going with my flying. One thing that got me quite nervy (as if I wasn't apprehensive enough), was that the wind was quite gusty today. Windsurfer  reported about 7 m/s (25 km/h) winds gusts with roughly 6 m/s (21 km/h) wind speeds. But in my mind (call me foolish) I thought this would be a good test of my hovering skills in the midst of all disturbances. After binding the heli, I took to the skies with the thumping heartbeat. The wind gusts in the open field started becoming more evident in the control of the heli. A couple of gusts even elevated the heli a few meters higher eventhough i had reduced throttle. Then a sharp gust almost caused the heli to barrel roll into the ground. But i kept my cool and decided to persevere through. I was tempted to allo...

Today during lunch time, took the heli out for another spin and consistently in my mind, I was wondering about the numerous time I stopped being careful after the first round of success and lost very expensive aircraft. So having such in mind, I took it slow and easy in a tail-in hover will a slight side hover. Halfway through the flight I decided (or the devil in me) decided to put the heli in a nose-in hover and my pulpitations started all over again. But was surprising was how stable the heli was even in the presence of mild winds. Managed to perform half a circuit and landed the heli once the 4min was up. Good job!

So it was my first flight with the Blade 300 CFX yesterday and like anything new, the rush not to end in an epic failure that will leave you gutted for days was upon me. After doing a transmission/range sweep I put the aircraft through its paces. Coming from the Blade mCPX heli, going through the structural modes of the heli caught me by surprise thinking there's something wrong with the heli, Anyway pushing through it, even with a slight breeze, managed to get the aircraft in the air and maintaining tail-in hover. Most of time was spent in getting a feel of the controls and the dynamics on the heli. It looks very responsive which made you think twice about having any sudden knee-jerk reactions on the radio controls. After 4min, I landed the heli with raw smiles all around my face. Good job!

So I've been battling to establish a simple method in mimicking rc control inputs during a sustained or coordinated turn of the aircraft. This is quite important as it's not the same as stabilizing controller which reacts to dynamic events while having a static reference. A coordinated turn has a dynamic reference which is coupled to the turn rate experienced which directly related to the speed and the roll command inputs. But since the turn rate of the aircraft can be extracted from the gyroscope measurements, it can be stated that post processing of these signals (using a low pass filter) should give an indication of whether such method can be used alongside a stabilizing controller. This is such that once a coordinated turn can be achieved even in adverse weather, waypoint tracking is closer to being realised. Amendment 15/1/2015: It was found after careful analysis of the flight dynamics of a simple aircraft that gyroscope measurements was not a fool-proof way of ...

So I had a brainwave the past two days in how to test various aspects of the autopilot modes without having to land and flash new software. It became very frustrating that for each morning, I had to land the aircraft 5-6 times and increase the risks crashing and even worse loosing the instrumentation on board the glider. This approach could potentially allow me to analyze various options of flight modes and optimize which one best suited for that function. The ultimate goal is of course, the speed at which each flight modes can tested. So I manage to devise a method that allows me to use a switching mechanism such that I can switch between each programmed flight modes by using transmitter only. The code was tested and seems to work just fine. Now it's just a matter of testing in flight.

deadband diagram (Photo credit: Wikipedia ) Managed to squeeze another flight test on Sunday morning (the usual madness occurred afterwards). Had about 7 - 8 hand launches to test the pitch autopilot with the gyro measurements integrated in the PID loop . It was quite that some adjustment to the how these inputs are being used was needed. So after each landing, adjustment to the gains was made. The erratic nature of the control requires a deadband filter approach which would enable the airframe to settle on a particular flight path naturally (restoring motion). A crude logic was implemented and tested and seemed to work although further test will need to confirm such approach. From a kinematics point of view, it makes sense and prevents excessive servo control usage which decreases the life of the part dramatically. Once confirmation that the logic is sound, the same approach will be made on the roll and speed autopilots which will allow us in the next 2-3 weeks move towards...

We've been having quite bad (windy) weather that It has been almost impossible to get the glider up in the air to gather more flight data . But nonetheless, I managed to analyse the data that I have come to some interesting conclusion on the behaviour of the aircraft in flight. The post-filtering of the IMU euler angles prior to controller design only add approximately 4/10th of the second in lag (guestimate). The servo limiter which I set on all channels is which what a normal flight actuation is experienced (considering wind factors). It's quite clear from the graphs that GPS velocity is expected to change with aircraft pitch although the nature of the sensitivity over a 1Hz update was not expected. The noise factor in launch in both roll and pitch channels shows that an alternative method needs to be established for a take-off and landing autopilot mode. There seems to be a considerable lag in pitch servo input and pitch change. This makes sense for the fact that t...

So I got some flight time under my belt yesterday. I must say there's nothing better than seeing your flying skills improve with time ( I can't wait to get more batteries so I can get my heli in the air as well). Anyway, back to the glider autopilot . Managed to get the roll autopilot to stabilize the aircraft which was a great feat. Although because the glider is inherently unstable during banking (due to the battery pack sitting on top of the wing) the roll autopilot relies heavily in controlling the rates produced by the aircraft. This is still a problem as roll rate doesn't yet have a strong influence in the control loop . The same can be said about the pitch controller (which I had to land the aircraft, upload new code and launch again). Due to the lack of control on the pitch rate, the phugoid mode of the aircraft is activated and the aircraft goes into an unstable dives which eventually would cause a crash. The use of the safety switch mechanism logic has ...

Depicts a traditional PID controller. (Photo credit: Wikipedia ) I'm such an exciting right now. It's been over a year of putting this UAV glider with custom autopilot and electronics together and now we're at the pivotal stage. In-flight testing of autopilot and GPS waypoint tracking!! Decided to go for a flight test on Sunday morning before church (around 7am) eventhough I was performing the church band that morning (crazy I know). It was bitter cold but decided to push through. I must say that I realised that I need a small collapse table/stool to setup the instruments instead of the wet/moist ground. I was great to see that the transmitter code works as expected. There was no lag in the transmission of signals from transmitter -> autopilot -> servos. The turning of aircraft with rudder and elevator control was smooth and consistent. It was refreshing to see that the filtering algorithm worked well. Decided to test the roll autopilot first, this...

If you want to use my graphic outside Wikipedia, and its resolution or license doesn't satisfy you, write to me: 100px (Photo credit: Wikipedia ) The radian glider took a real beating at the last crash. Although it had a 'soft' landing eventually, going through the trees was not pleasant the foamy airframe . since it wasn't covered, indentations can be seen all over the aircraft.