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idea for return to home

Discussion in 'General Discussion' started by Suwaneeguy, Jul 2, 2014.

  1. Suwaneeguy

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    You are standing on level ground and want to fly your bird over the building in front of you that is 100 ft high.
    Let's say maybe something like a large covered sports dome.
    On the other side of the building, you lose contact. RTH is engaged.
    The bird does its thing and flies to 20 meters, checks bearings and returns home.
    Crash! The bird just found the side of the building.

    How to prevent this?
    One way could be to record various positions and altitudes while in flight.
    So the bird should know that returning home via those points is safe.
    Like having its own waypoint system.
    The next question is, can the bird return home in the allotted time the battery has remaining?
     
  2. chuddly

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    its possible....but nothing is written right now to do that. at that point you could only fly to 50% of the battery (in theory) and still make it back to land. because the phantom would have to retrace its course to guarantee that it doesn't fly into something. all it knows is that from way-point 1-2 was clear and 2-3 was clear and 3-4 was clear. If it is at way-point 4 and needs to land at way-point 1 it doesn't know if a building or tree is between 4 and 1 (as the crow flys). This means it would have to retrace its entire route to know it was flying in good airspace.
     
  3. sar104

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    You can effectively do this already, simply by taking the aircraft straight up from takeoff to an altitude above any nearby obstacles of concern and then resetting the home point. If RTH is triggered then the aircraft will ascend to 20 m above the home point elevation before returning - well above any obstacles.
     
  4. gverila

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    Hello, maybe a stupid question but how to reset home point? Thanks.
     
  5. QYV

    QYV

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    it's not stupid but it's an advanced concept. You have to switch your flight computer from the default mode called Phantom Mode, to the advanced mode called Naza Mode, but that opens up a whole new can of worms.

    Naza Mode enables the 2 toggle switches on the remote control (that in Phantom Mode don't change any flight parameters) - the one labelled GPS/ATTI . Once in ATTI mode, the other toggle is enabled for the CL (course-Lock) and HL (Home-Lock) flight modes. Also I understand there's a full manual mode with no flight assists (basically, you'll crash) .

    anyway you have to be in Naza Mode and you flip one of the toggles rapidly (I think 5 times) and the green lights on the phantom will do their rapid-blink sequence indicating a new Home Point has been set. Whatever altitude you were at, now becomes the zero point from which the Phantom will go +20 meters if RTH is triggered.

    Sorry I'm fuzzy on the details I'm perfectly happy in Phantom Mode so I've never gone into Naza. I would definitely research ATTI, CL, and HL heavily before enabling them as they drastically change the way your controls on the RC operate the Phantom. there's plenty of youtube videos and threads around here talking about it
     
  6. sar104

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    You don't have to enable Naza mode to reset the home point. In Phantom mode, under GPS flight, you can reset it by flipping S2 from upper to lower position and back five times.

    Also, Naza mode doesn't change how the aircraft responds to the controls, it simply enables some other flight modes (ATTI and MANUAL) and some extra functions (course lock and home lock). It has no disadvantages.
     
  7. QYV

    QYV

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    That's contrary to what I've seen people around here say before, I'll be very glad if I'm wrong I was wishing I could use that feature in Phantom mode. haven't had any flight time to test recently.

    I'm afraid I politely disagree with you on that one.. if you flip into ATTI + CL or HL modes, lateral controls are no longer direct fwd/backward/left/right for the Phantom... they're now relative controls to the home point. To me, that's changing how the aircraft responds to controls.... if someone gets into CL or HL mode without fully understanding what they do they may not udnerstand what's happening when they press the stick.

    I didn't say there was a disadvantage, just that it's different and I feel my primary point that proper education is essential before entering ATTI / CL / HL is valid, even of my wording could have been better. bear in mind the person asking the question has a 1 post count I don't think it's right to assume he's a seasoned pilot
     
  8. sar104

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    For obvious reasons, I recommend reading the manual, rather than going on what people around here say. From page 24 of the Phantom 2 user manual:

    In Phantom 2 mode, users can set a new home point manually when the aircraft is in “Ready to fly” status as long as a home point has been recorded automatically. Quickly flipping the S2 switch of the remote controller from upper most to lower most positions 5 times or more will reset the current aircraft position as a new home point of PHANTOM 2. When successfully reset, you will see a series of rapid green blinks on the LED Flight Indicator.

    Personally I've never used Phantom mode so I can't vouch for that, but I would guess that it is correct.

    Fair enough - but it is enabling those modes (CL or HL) that affects the behavior, not simply switching to Naza mode. If, on the other hand, pilots are flying without even reading the manual, as this conversation clearly demonstrates, then I guess up/down/fowards/backwards really is the appropriate level of complexity.
     
  9. MrC

    MrC

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    Just an option to change the rth height would suffice.
     
  10. gverila

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    Sorry guys but I didn't mean to start any dispute. Thanks for all your answers. So is this with S2 switch also available in naza mode?
     
  11. QYV

    QYV

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    don't sweat it mate... communities like this are how we learn and I for one definitely want to know when I'm mistaken, as with the setting a new home point height in Phantom mode. It's not the first and probably won't be the last time :)

    We're on the same page now, my phrasing could probably have been better before Sar is right. It's not the Naza mode itself that's the problem, but once you're in Naza mode the switches, if toggled, change the way the Phantom responds. Fortunately it doesn't matter you can utilize that feature in Phantom mode I'm pretty stoked... although now that DJI keeps nerfing Phantom Mode more and more I'm probably going to be checking out Naza/GPS mode.

    I always check that my toggles are both up before my first flight even though they don't really do much in Phantom mode (unless you've set the right toggle to trigger failsafe), but plenty of times in all the goings-on flying, passing controllers around, whatever I'll notice that one or more of the toggles has gotten flipped. In Phantom Mode that's a non-issue but in Naza Mode an inadvertent toggle could be quite disorienting.
     
  12. Suwaneeguy

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    Ok so I reset my RTH to 100m above my ground location.
    When engaged, the bird returns to that position, checks the location, verifies and politely shuts off the motors.
    Down comes the bird in a heartbeat.
    IMO, it should retain the original RTH location so that it knows where ground is.
     
  13. OI Photography

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    You had it right up until that part. The recorded height of the home point is only used for the Phantom to determine how high to fly on the return trip (i.e. home height + 20m). Once it starts gets over the home point and starts descending, it will continue to descend slowly until it senses that it is not descending anymore, presumably only after it has reached the ground or other landing surface. It doesn't just shut off the motors in midair when it reaches the recorded home point height. If that were the case, the feature of resetting the home point would crash every single Phantom that used it.
     
  14. MrC

    MrC

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    Yep, it will just keep descending slowly until it hits the ground.

    OI, does the recording a new home point at altitude thing actually work then? I seem to see people still arguing if it does or not. Have you tried it? I may have a go next time I fly.
     
  15. OI Photography

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    I don't think I have, if I did it was so long ago I don't remember (which could mean last week lol). I know I've seen reports of it functioning as intended, effectively adjusting not only the 2D coordinates of the position but the starting height for RTH calculations as well. To be honest, I don't seem to recall seeing any conflicting reports, but I think I'll give it a shot tomorrow.
     
  16. sar104

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    It's slightly different in Naza mode - same switch, but toggling serves dual function. In Naza mode S2 positions are OFF / CL / HL. Toggling OFF -- CL 5 times resets the course lock, while toggling CL -- HL resets the home point.
     
  17. sar104

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    Yes - to clarify - resetting the home point resets both 2D position and altitude, and when the aircraft does RTH it will simply descend through the home point until motor shut down is triggered by no detectable descent for 3 seconds or more - i.e. it has landed.
     
  18. Suwaneeguy

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    Thanks for the reminder ol photography.
    Maybe that's why they built in the 3 second thing.
    I will try this sometime this weekend if it ain't raining.

    What they could do rather easily, is install a laser measuring device.
    Then compare the laser signal to the gps altimeter setting.
     
  19. gverila

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    Thank you very much for explanation.
     
  20. Pilot_FML

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    MrC,

    Just read your post and to answer your question, setting home point (HP) at altitude definitely does work. Zbip57 (a poster on the rcgroups forum) posted a video that actually walks you through steps verifying how to change the HP while actually flying. His video then shows the Phantom actually flying to the changed home point location (when Failsafe was actuated), rising 20 meters above that inflight altitude and then slowly decreasing in altitude until it touches down. The motors DO NOT shut off until it touches the ground. If your interested here's the link to his video:
    http://www.rcgroups.com/forums/showpost ... ount=26564

    P.S. While in the rcgroups forum(s) search for other videos Zbip57 has done. He's clarified (via video) many of the flight control claims made by the Phantom flight controller.