Waypoint flight - the ghetto way?

[Shrimpfarmer]

Good point about the props being off and also the info about how little power it uses just sitting there. Small field tests needed now. Set home location, pick it up and move it to the other end of the field. Take off hover at 200ft walk back to the landing site and hit failsafe. I am grounded today but will certainly experiment with this when I can.

 

[Pull_Up]

Spec. says: "Max Flight Speed 15m/s (Not Recommended)", but that is (?) airspeed. Relative to the surrounding air, not relative to the ground.

Sadly it doesn't have a pitot tube and air speed instrument in it (that would be cool!) so it's only reference to speed is ground speed calculated from GPS data. This means it will put a bit more angle on in a head wind to maintain its programmed speed, and a bit less in a tail wind.

In a very strong headwind it could end up stranded if the max tilt angle isn't sufficient to compensate. It's always worth, if you can, operating upwind of home position. It will also help if the battery level gets low - heading into a headwind will use more juice trying to get back.

 

[Shrimpfarmer]

Does a phantom returning home but not there yet when the battery gets too low initiate a landing or fall from the sky? My gut feeling tells me it lands.

 

[Pull_Up]

Low power initiates an autoland in normal use, I have no evidence that it would do that whilst in RTH but can't see why the algorithm would ignore that if in an RTH situation. That aside, however, it will only keep coming down gently for as long as it's got power to do so - if you're 20m up, not so risky. If you're 200m up...

 

[Scottrod]

I would imagine even if it's already in RTH mode it would still start to auto land the moment that the battery hits the low threshold amount. Maybe and hopefully I'm wrong.

 

[AnselA]

Spec. says: "Max Flight Speed 15m/s (Not Recommended)", but that is (?) airspeed. Relative to the surrounding air, not relative to the ground.

Sadly it doesn't have a pitot tube and air speed instrument in it (that would be cool!) so it's only reference to speed is ground speed calculated from GPS data.

Maximum airspeed is a feature, which depends on the design, selected components, software, etc. GPS based speed calculations will not change the maximum speed Phantom is capable to achieve.

 

[Pull_Up]

Yes, but I thought you were referring to the comment about the RTH speed. In RTH (and Home Lock, for example) the aircraft does not fly as fast as it can, but at a speed set by software (on V1 Phantom with ground station you can specify what speed it should fly between waypoints manually, too. Hope that feature comes with the Vision firmware update). All these set/selectable speeds are in relation to GPS-derived ground speed, of course. You are right, though, in that if the head wind is strong enough the Vision won't be able to compensate due to the maximum angle of tilt it is physically able to achieve to give forward flight and still provide sufficient lift to hold altitude.

 

[dkatz42]

Yes, but I thought you were referring to the comment about the RTH speed. In RTH (and Home Lock, for example) the aircraft does not fly as fast as it can, but at a speed set by software (on V1 Phantom with ground station you can specify what speed it should fly between waypoints manually, too. Hope that feature comes with the Vision firmware update). All these set/selectable speeds are in relation to GPS-derived ground speed, of course. You are right, though, in that if the head wind is strong enough the Vision won't be able to compensate due to the maximum angle of tilt it is physically able to achieve to give forward flight and still provide sufficient lift to hold altitude.

It may be that RTH uses a target pitch angle rather than a target speed, which might make the most sense in terms of control stability. We'll never know without the source code.

 

[AnselA]

I was thinking to estimate the (minimum) time needed to fly from one location to another. Wind speed and direction definitely has an effect.

 

[NEILS]

Did anyone look at this further

 

[Scottrod]

I plan to try it as soon as we melt some of the snow

 

[LandYachtMedia]

I have not done exactly this but I did notice something last weekend when I was flying.

I had to boot up in the yard and let everything lock in but I took off and landed from the street in front of the house. Now what was interesting is that I let everything go through the process and get the green flashing lights. I also got the solid GPS indicator on the iOSD indicating a home position was recorded. I then picked up the Phantom and moved it to the takeoff location about 60' away. I noticed that the GPS symbol on the iOSD was flashing and it gave me the rapid green flashing lights just before I started the rotors. This is on firmware 1.08 on a P2 (non-vision).

When I took off the iOSD definitely indicated the HOME location was where I took off from NOT the location where it booted up and got first sat lock and location. It looks like moving it far enough from its original home location was enough to trigger another home position lock.

 

[Pull_Up]

Is it because of this, maybe? Under Home Lock :?:

Method of Forward Direction and Home Point Recording
If you use the IOC function, please be aware of the Forward Direction of Course Lock Flying, and the home point of Home Lock Flying. There are two ways to record the forward direction and the home point: Manually and Automatically. You may choose any one record method. The LED will blink Green quickly if successfully recorded.

EDIT: Not formatting correctly, direct link : http://wiki.dji.com/en/images/a/af/Nzmv2-ioc4.png

 

[Buk]

Pull-Up,

When you look at your attachment, do you ever think the words "Manually" and "Automatically" should be reversed?

Although you can find other references,

Home-point: Before takeoff, current position of multi-rotor will be saved as home-point by MC automatically when you start the motors for the first time after 6 or more GPS satellites are found (red light blinks once or no blinking) for 10 seconds.

 

[Pull_Up]

I reckon you're right - I never noticed it before! It's taken from the Naza-M-V2 wiki and dated May 2013...