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Everything posted by Spitfire76

  1. The file is part of the source code which is available on GitHub. You will need to setup a development environment http://ardupilot.org/dev/ Its a bit involved if you are not familiar with compiling software. This does not avoid changing and compiling the code for the RTL return altitude to be below 2m. What it typically provides is a more accurate way for the flight controller to measure its altitude which is of course more important when the UAV is close to the ground. However it looks like the Pixhawk4 is equipped with a MS5611 barometer that's reported to have a resolution of 10cm. I am not sure though if that means if the UAV is at 50cm it could actually be between 45-55 cm or 40-50 cm. The Terrabee Eco 60M has a reported accuracy of +-4cm at 14m and below so not much more. When you fly the UAV at 50cm is it stable or does it bop up and down ?.
  2. Here is what I found. The behavior is not caused by mission planner but its hardcoded in the ArduCopter firmware's config.h file. # define RTL_ALT_MIN 200 // min height above ground for RTL (i.e 2m) It looks like to change it you would need to recompile the software. 2m is quite low for outside, especially considering the accuracy of the barometer. Why do you need to fly so low ?.
  3. It was the topic on Ian Smith's latest Commercial Drones FM podcast. https://commercialdrones.fm/podcast/flyability-patrick-thevoz/
  4. I just checked this by testing with SITL (Software in the Loop) and even though I set the RTL_ATL to 0 when RTL is triggered it does climb to 2m instead of maintaining its current altitude of 0.5m. 2m is of course 200cm which is what the documentation is stating as the lowest value that RTL_ATL can be set to although in mission planner it does allow you to set it to 0 and states that with 0 it should maintain its current altitude which is not the case when the current altitude is below 200cm. I'll check into it a bit further as maybe there is a good reason for the minimum 200cm altitude.
  5. The way that RTL works is that once triggered the craft will climb to RTL_ALT (or maintain its current altitude if RTL_ALT is lower). The idea here is to avoid any obstacles like trees or buildings as the return path is a direct flight path to the launch location which could be difference from the outbound flight path. My understanding of RTL_ATL_FINAL is to tell it what altitude you want it to be once its reached the home location and setting it to 0 will cause it to land but maybe you don't want it to land but hover at a certain height. If you simply wanted the craft to automatically land once the failsafe was triggered just configure LAND mode instead of RTL in the failsafe screen.
  6. Hi @Chase Flynn | UAV Coach This is the first time that I've studied the rules this early on in the competition and now I am tempted to come up with a design to meet the 2020 challenge. It looks like its going to require 2 aircraft, potentially a fixed wing as the transient craft between the base and the remote accident site that carries a multi-rotor type craft that is deployed to enter the shed to provide the communication between Joe and the medical rescue team that's on route,
  7. You maybe aware of this but in stabilize mode the throttle simply determines the speed and therefore thrust of the motors. Were you expecting a more controlled decent ?. If so you might want to try descending in Alt hold or one of the other modes that uses Alt Hold to control altitude. http://ardupilot.org/copter/docs/altholdmode.html#altholdmode-controls As you will see in the above in Alt Hold mode the throttle stick is now controlling the rate of climb or decent rather than simply the thrust of the motors. Also note that a range finder like we have discussed in another thread is good to have if you are using this mode as its more accurate than the built in barometer of the flight controller that uses air pressure to sense altitude.
  8. It looks like if you use one of their Evo series sensors then power is obtained from the Pixhawk. https://www.terabee.com/connection-to-pixhawk-autopilots-teraranger-evo/ What you may need though is an I2C hub as your compass maybe already be using the I2C port but I would need to check into that further.
  9. https://www.terabee.com If the sensor is pointing down it can be used as an accurate way of measuring the distance the aircraft is off the ground. Yes, if mounted horizontally and configured appropriately although several sensors would be need for all round collision detection. https://www.terabee.com/shop/lidar-tof-multi-directional-arrays/teraranger-tower-evo/ No a big deal, in that case you just add a BEC that supports a 6S input voltage and provides a 3s output. Again, I have not used any of their products so I can't say if they work well or not although as I mentioned before I am considering using one of their products for use in a fixed wing UAV. Also I may look into their EVO sensors rather than their first generation Terra Ranger One. https://www.terabee.com/sensors-modules/lidar-tof-range-finders/
  10. I've never had to mess the those values so I can't say why its not working. In my experience of building several drones using ArduCopter the default values have worked fine although I do plan on using the "Autotune" flight mode one of these days. I believe that it just changes the PIDs though for roll, pitch and yaw and not throttle. Have you had experience with other drones ?. I ask because when I first started flying my landings were not exactly soft and it took some practice to land well.
  11. Looks like some of these changes are just now kicking in...... https://www.suasnews.com/2019/05/faa-highlights-changes-for-recreational-drones
  12. Spitfire76

    Throttle P value

    Did perform radio and ESC calibration ?. http://ardupilot.org/copter/docs/common-radio-control-calibration.html http://ardupilot.org/copter/docs/esc-calibration.html Have you changed any of the PID settings ?. Does it also land hard when you switch to RTL ?
  13. Spitfire76

    Throttle P value

    What flight mode are you in when landing ?
  14. Version 1 of the competition rules for the UAV Challenge Medical Rescue 2020 have been posted. https://uavchallenge.org/medical-rescue/
  15. I thought that Bob Watt's podcast on hydrogen fuel cells for use in drones interesting. His company, WattsInovations has been testing a fuel cell from Intelligent Energy http://highvoltagepodcast.com/12-reasons-why-a-hydrogen-fuel-cell-powered-drone-might-just-work/
  16. DJI released a new product earlier today. No event just an update to their website. https://store.dji.com/product/osmo-action
  17. It is but I would not rely on the barometer that's in the flight controller. You need a more accurate range finder at low altitudes. http://ardupilot.org/copter/docs/common-rangefinder-landingpage.html I've used an ultrasonic one as it was the most economical http://ardupilot.org/copter/docs/common-rangefinder-maxbotix-analog.html but if I were to add one these days I would try out one of these http://ardupilot.org/copter/docs/common-teraranger-one-rangefinder.html I'm currently building a fixed wing drone and a rangefinder is essential for antonymous landing so will likely use one of those although they are that cheap.
  18. I tried this on the ArduCopter SITL and although it does warn you that the value is out of range it does give you the option to continue and change it. So yes you can set it to 2 m but again the GPS is not so accurate so having such a low radius may cause problems.
  19. It looks like the FENCE_RADIUS parameter range is 30 to 10000m so I suspect you will get an error if you try to set it lower. Typically the GPS is only accurate within a few meters, same with the altitude unless you are using a lidar range finder instead of the onboard barometer. I believe that GPS RTK is more accurate (down to a few cm) but I have no experience with its as it out of my budget.
  20. You can use mission planner to configure a GeoFence. http://ardupilot.org/copter/docs/ac2_simple_geofence.html P.S I've noticed that your posts are appearing in the pilot lounge catergory but the DIY would be more appropriate.
  21. 50% throttle is roughly when the throttle is in the center. More information here http://ardupilot.org/copter/docs/ac_throttlemid.html#automatic-learning-of-hover-throttle You can select which compass to use on the compass calibration screen in MP. http://ardupilot.org/copter/docs/common-compass-calibration-in-mission-planner.html
  22. The throttle should be around 50% to hover when in stabilize mode. There is a "dead zone" in loiter mode which I believe is between 40 - 60 % throttle in which the drone will maintain altitude. Moving the throttle outside this range will increase or decrease the altitude. If you haven't moved the throttle back to the hover position of around 50% then when you change from loiter to stabilize it will use that new throttle setting and suddenly increase or decrease in altitude.
  23. The range of that camera looks pretty small, I think its more suitable for short distance thermal measurements than longer distances that would be needed for use on a drone. The thermal cameras used on drones seem to be in the several thousand dollar price range. A couple of camera companies that I've been following for potential use on my DIY drones are https://www.mapir.camera https://openmv.io
  24. What flight modes did you test ?. Was this the maiden flight ?. I typically test stabilize mode first as this only uses the gyro and accelerometer. If that works ok I switch to loiter which tests the GPS and compass. I also might test alt hold mode as this uses the barometer to maintain altitude. Finally if those work I'll test RTL. Its really important that some of the sensors are thoroughly calibrated before flying. Did it fly better in siome modes than others ?. Make sure that the only compass that is being used is the external one in the GPS. Also make sure that it is properly calibrated..
  25. UAV camera gimbals usually have some sort of interface for controlling pitch and pan via the same radio that is used for controlling the UAV. For example the camera gimbal that I used on mine awhile ago was the Tarot T4-3D which has both PWM and S.BUS interfaces and so connects to the same receiver that is used to interface to the flight controller. I just assigned a couple of slider controls on my transmitter to control pitch and pan. If I was planning to build a more professional UAV then I would consider Gremsy . Also in some high end UAVs you might want to have a 2 operator configuration, one flying the UAV and one operating the gimbal and camera in which case you would install 2 receivers.