MPCC Crash

misterfeathers · Feb 27, 2017

Was flying with a MPCC with 5 points. Starting altitude was 10ft above ground. When I loaded the cable the drone immediately flew to what appeared to be a waypoint below the ground. Was able to recover just after tapping the ground. Is this a known bug with MPCC to have altitude drift and waypoint drift in the cable or does this warrant submitting a ticket to 3dr?

Any advice on increasing stability of the loaded MPCC. I even flew it manually to confirm waypoints and still had problem. Does the Solex app have better performance in this area?

GPS and transmitter signal were all in the green.

Pedals2Paddles · Feb 27, 2017

The smart shot is firmware on the solo. It doesn't matter what application you use. The application is the user interface to the program on the solo.

MPCC forms a curved path through and around the points you set. The shape of that curve varies based on the prior and next waypoint position, speed, and how sharp the turn is. It does not necessarily hit that exact spot. Rather it forms a nice smooth move through or just around it. This applies to both horizontal and vertical paths. Unplanned impacts with the ground are a common new user mistake in MPCC. I accidentally mowed some high grass doing that too. Combine that with barometric pressure changes, wind, etc, which can make your altitude deviate by a few inches or a few feet from reality.

Maddog · Feb 27, 2017

I have discovered that MPCC (and possibly other smart shots) accuracy isn't always great at low altitudes (say around 10' or lower).

Like P2P said barometric and GPS accuracy isn't as good at lower altitudes.

I was setting up a MPCC to fly around my house and film the edges of the roof. After Solo started flying the shot, it got so close to the house I had to stop and just fly it manually. At times it dropped down to about 5' and almost hit the fence.

SteveReno · Feb 27, 2017

I read somewhere? Rule of thumb for most MPCC flights is that a 5 to 10FT margin for MPCC.
I do it in the middle 7.5 of margin. You must account for barometric pressure changes, wind, etc. Just like Pedals2Paddles mensions above.

Perhaps a more precise GPS system will lower this variance in MPCC. flight

my-spot · Feb 27, 2017

MPCC is spline based and I believe that includes altitude also. So that means that while your waypoints might be above ground level, the resultant path Solo flies between the waypoints might go below GL. Example: imagine a MPCC with 4 equally spaced points with the following altitudes 100',10',10',100'. The path flown between the two 10' points will very likely go below GL... However, I have never tested this assumption about altitude because I understand splines and don't want to fly my Solo into the ground

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I also assume that any given point (altitude and/or GPS) is only good within about a 10' diameter (at best) so I set my points accordingly - not flying too close to objects, ground, etc.

misterfeathers · Mar 3, 2017

Great thanks for all the additional information. I'm still trying to find a work around for flying a MPCC at low altitude. Is it true that the spline is based on only previous and next waypoints? I'm thinking that if I set numerous way-points at the low altitude and slowly climb up in altitude the relative difference between the low altitude points will have a smaller spline curve? I saw something similar to this with sharp corner turns. Thoughts on feasibility?