Hi,

 

Open source autopilots are widely used in the RC toys. I tried 3DR's pixhawk. It seems to be quite okay. There are also other open source autopilots.

The commercial autopilots are always used in commercial unmanned aircraft. They are somehow much more expensive than open source. I’m wondering what are commercial autopilots’ typical advantages compared with the best open source autopilots for conventional fixed wing usage. Could anyone give any hint on that?

 

Best,

Anna

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    • Hi Gustav,

       

      I'm interested in using it in the commercial UAV we designed.

       

      I start to learn and use Pixhawk recently. I found that it was not very stable when I tried to connect it to my computer. The software Mission Planner and QGC usually failed to connect to the Pixhawk. I usually need to reload the firmwire again and again to make it work. And the airspeed sensor sometimes give quite strange data. Maybe that's because I'm a beginner of it and not that familiar with it.

       

      May I ask do you ever have the same experience? 

       

      Best and thanks,

      Anna

      • Hi Anna,

        I only have APM 2.5 and APM 2.6 controllers.

        But I have no problems with Mission Planner, on two different laptops, one running 32bit XP Pro, the other 64 bit Win 8.

        I only use Mission Planner.

        I can connect with either the cable, or 915 MHz modems. I found that the antennas that come with the modems vary in quality.

        The antennas supplied by 3D Robotics shop work well, the ones you get from some Chinese companies that sell clones of the 3DR products, don't work all that well.

        You can also use some cellphone antennas, I use some products made by Taoglas.

        The airspeed sensor for the APM is an analog device, I do see some fluctuations even just sitting still, maybe 2 Km/h or so, doesn't affect the flying.

        Regards,

        Gustav

      • Hi Anna,

        Where did you buy it?

        • I have two Pixhawk board, one from 3DR and another one from a Chinese factory (we may call this 'pirate' one). The 3DR one has shown non better performance or stability than the 'pirate' one up to now from my experience. I have one 3DR 6H GPS, one 'pirate' 7N and one 'pirate' M8N GPS. All of them are usually and randomly hard to be activated. 

          Btw, we can see the transaction record from Alibaba's Chinese website that the 'pirate' one sells more 80 Pixhawk boards online per month in China. The boss of that factory declares that he sells more than 500 per month all around the world. 

          Has anyone used the 'pirate' Pixhawk boards? What's your opinion on them?

           

          • Hi Anna,

            APM, PixHawk are all open source.

            All the drawings and schematics are open, and can be copied.

            And since most components come from China, Malaysia and Korea anyway, the only difference will be in quality control of the finished product.

            I respectfully suggest, if you see no difference between the boards, that your team is doing something wrong.

            Setting up an autopilot, whatever make, requires a fundamental understanding of radio frequencies, power distribution, and airframe design and layout.

            If you give definitive descriptions of the problems you experience, maybe some one here can help.

            Of course, if you can afford to fly a Gweilo like me over there...... :-)

            • I don’t get your point. Why I shall see some differences between these two boards if the only major difference is the quality control?

               

              I haven’t flied the Pixhawk a lot yet. I just bought two Pixhawk as stated above. The main problems I got are: The software Mission Planner and QGC usually failed to connect to the Pixhawk. I usually need to reload the firmwire again and again to make it work. And also I usually need to shut down the Mission Planner or QGC and restart it to make it to be able to connect to the board. GPS often can not be activated outdoors. I need to restart the board a lot of time to activate the GPS. The problems are equal for 3DR’s and ‘Pirate’ Pixhawk.

              • Unfortunatly, there is no such education today, the University in Tromsø, and some others, started up UAV related education, but that's mostly about general flight, data collection, payloads etc.

                You need somebody with extensive experience from Ardupilot use, as well as RC flight, familiar with creating a POH and doing commercial test-flights /(the last one can require a minimum of logged flight hours of CAA approved oparations.)  - at least my countrys CAA *liked* that before doing commercial test flight. - Not an absolute requirement - but I used that argument when applying for this kind of operation.

                • Do we also need an engineer with theoretical knowledge in both flight control theory and flight mechanics? There are aerodynamics and flight mechanics engineers in our team. But we don't have an 'flight control engineer'. Does 'use' Pixhawk for my application requires a lot theoretical background in control system?

                  I was thinking about hiring an engineer with a background in flight control theory. It seems that at the beginning of the attempt to use Pixhawk to fly my UAV, the knowledge in those flight control algorithm is not essential.

                  By the way, what does 'POH' stand for? I googled it but didn't find a relevant explanation of this abbreviation.

                  • 'Using' and tune Pixhawk/APM is quite essential if I want it to perform well. What knowledge or background it needs besides extensive experience on it?

              • Hi Anna,

                How do you connect to the PixHawk?

                Yes, I also sometimes have to restart Mission Planner, but only if I interrupt it during some process, like downloading log files.

                You should not need to repeatedly install the firmware.

                The actual GPS engine is completely separate from PixHawk.

                The fact that two completely different boards are showing the same problems points to some other operating problem.

                Maybe you should supply info on your setup, even maybe some pictures.

                Darrel and others gives good advice and pointers.

                Regards,

                Gustav

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