Better control in Height Mode?

Discussion in 'ALTA' started by Cesar Fernandez, Dec 28, 2015.

  1. Cesar Fernandez

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    I am learning how to fly my new ALTA and the instructor recommended to try to fly in manual mode if possible, however, I have found that in HEIGHT or Position Mode the drone is much easier to control and fly a lot smoother. It also tends to hover nicely and steady, which would be easier for photography and video.
    Is this the same experience for others?
    Are there other benefits in which Manual Mode is preferable than Height or Position Mode?
    Thanks for any advice.
     
  2. Steve Maller

    Steve Maller UAV Grief Counselor

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    Like any automatic control system, it can fail or misbehave, so you should be able and willing to override the system and fly it manually. As for altitude hold, I've found it to be very reliable, but I NEVER use it during takeoff or landing, for example. And I've found under very high-speed maneuvers or in high wind it's not 100% reliable (which is to be expected because of the way it's implemented) so you should be able to bypass it.
     
  3. Mateusz Hajdziony

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    Steve, why do you take off in manual only? What happens if you take off/land in ALT hold? Curious to know your experience with ALTA as I am using DJI A2 and ALT hold mode doesn't cause any issues during takeoff and landing with this controller.
     
  4. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    I always take off and land in manual mode so that I'm ready for the day the automation fails.

    As Shaun Stanton remarked on another thread, flying the automation is boring! :rolleyes:

    Andy.
     
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  5. Cesar Fernandez

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    Keep in mind that I am still in the learning stage. I have been flying in manual mode but I found rather tricky, if not difficult, maintaining a steady position (hovering), specially if there is any breeze. Also, the drone will loose altitude as soon as I perform any maneuver, in other words, if I travel from point A to point B, the drone will not maintain its altitude and I have to keep adjusting it all the time. The same if I perform any yaw, pitch or roll. Landing in Manual mode is also tricky. It looks like it respond a bit too much to minimal stick commands. I have found that on Height Mode or Position Mode it flies like heaven: very smooth and very controlled. It tends to maintain its altitude a lot better and landing is a breeze. I found myself switching from Height mode to Manual back and fourth when I want to regain control and feel more secure. I guess the analogy is like the amateur photographer, always wanting to shoot in "Program" mode.... As a photographer, I always shoot in "Manual" mode and nothing else.... it is always nice to keep total control of all parameters.... THE IRONY OF THINGS... ja, ja, ja... go figure. I guess one day in the distant future I will be flying on Manual Mode, but for now.....
     
  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The height loss when you maneuver is a normal thing, Cesar. It's caused because the "centre of lift" (the lift vector that points straight up when you hover), is deflected off to one side -- and therefore produces the required horizontal movement (otherwise called "translation").

    When the thrust vector is deflected to one side it reduces the vertical component available to lift the ALTA (or any copter, for that matter), and thus the copter descends.

    To reduce the sensitivity of the controls, try increasing the amount of "exponential" for the yaw, pitch/nick, and roll. The exponential refers to the graph of the curve you get when you de-sensitize the stick movements when they're close to their center positions. Do a Google search for: RC exponential (putting the "RC" in means you will get more relevant hits. Radio Control, in case you were wondering.)

    Height hold and position hold, as well as the velocity clamps are designed to make flying easier for you, but it's like cruise control in a car -- you better be prepared for them to fail at the maximally inconvenient moment. The GPS is likely to fail when there is a solar flare -- check out n3kl.org and look at the lower central chart -- and do a Google search for the Kp Index. Do NOT rely on GPS when the Kp Index > 4.

    Hope this helps.
    Andy.
     
  7. Mateusz Hajdziony

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    In addition to what Andy said, I assume that you are flying without any payload. If that is the case - it is completely normal for the craft to be really sensitive to throttle commands. A multirotor like that is really designed to fly with payload and it is not pleasant to fly without it - too much power to weight ratio will make the bird nervous. This doesn't happen in height (and position) modes because you don't have any direct input to the flight. In height mode your throttle only commands either 'hold altitude' (on +/- 50% stick) or descent/ascend speed. That's why the flight is really smooth, because the Synapse is doing most of the work for you. The same happens in position mode, but in addition to altitude hold, the FC controls X and Y position of the multirotor based mainly on GPS readings. Here your right stick only commands the speed, as opposed to the angle of the aircraft in manual.

    It's good to learn to fly in manual mode and actually aim for doing it whenever possible. Good manual mode skills will let you perform flights in windy conditions (where there would be too much wind for height hold to work) or where GPS is not available (or cannot be used due to sun activity). There are also times where flying in manual mode is a suicide (like really long range flights without FPV), but you shouldn't try these without really solid control and orientation skills.

    I would also recommend buying a cheap quadcopter to play around with in your free time. This will boost your skill level really fast because you'll be able to train high speed maneuvers without any worries of crashing $12k copter. :)
     
  8. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The AeroSIMRC simulator has a Cinestar 8 model. It's much cheaper to crash that than an ALTA. :)

    ANdy.
     
  9. Cesar Fernandez

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    Andy and Mateusz, thanks a lot guys. It makes all the sense in the world. I understand now the fact why the ALTA is so sensitive "without" the payload. Yes, I have been flying it without the MOVI and the camera, and I see why all that weight added would help to stabilize the drone. I will keep trying manual mode and I also have a small drone which I am also practicing as well. I will start adding the MOVI and the camera as well in short fly until I feel more comfortable and in control and then will start doing some camera operation (pictures and video) before I take it on a real trip. Thank you again. This forum has been invaluable.
     
  10. Michael McVay

    Michael McVay Active Member

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    Something else you can do when practicing with your Alta is use the lower battery tray to hold extra batteries as dummy weight. You can almost simulate the weight of a Movi and camera that way.
     
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  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    House bricks work well, too. AMHIK. :rolleyes:

    Andy.
     
  12. Dave King

    Dave King Well-Known Member

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    I always take off in full manual mode, hover to 20 feet, turn on altitude hold, and then if I am going to use PH I will flip it on then start my framing. I use AH in 99% of my flying, and never had an issue with AH.

    With all my copters prior to the Alta, I always landed with AH on and PH on (if used) and never had an issue. In thousands of flights I have never had a problem landing with the automation engaged. I have always found the problem to be on take off's and initial flight. With the alta I hate the fact you "MUST" be in fully manual mode on the ground to turn the motors off. IMO this is an accident waiting to happen.
     

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