P3: What if one motor goes out?

[Jaybee]

Woah! these guys are in the zone, check this:

Stability and control of a quadcopter despite the complete loss of one, two, or three propellers

 

[N017RW]

Yea, this is old. At least the proven concept is.

The low-tier FCs used in these quads is not capable of this.
Not to mention the power to weight ratios.

Notice no l-gear, no gimbal, no camera, no antenna mods.

 

[F6Rider]

Look again, he clearly controls it and lands it safely at 0:40:

Not that video, the prop loss crash in the river.

 

[ATPUFS]

I think parachute... When a sensor detects extreme increase or decrease in rpm on a motor, it shuts them all down immediately, deploys chute.

I actually don't think this would be very difficult to incorporate.

 

[Morgon]

I think parachute... When a sensor detects extreme increase or decrease in rpm on a motor, it shuts them all down immediately, deploys chute.

I actually don't think this would be very difficult to incorporate.

DJI did announce a DropSafe system, but for their larger platforms.
http://www.dji.com/product/dropsafe

It would be nice to see them miniaturize this enough for Phantom/Inspire use, but I'm not sure if physics would get in the way of keeping the same ability in a smaller package.

 

[johnp44]

Aside from physical or foreign object damage motors can't fail alone.
Bearings are the only wearing parts.

I had a motor failure that took my Phantom into a death spiral. No way in hell to save one from that situation. The amazing part was while the motor windings cooked/blistered and locked up the motor, the ESC was still functional. The failed motor spun the prop off so it must have been a very abrupt stoppage. When I reviewed the flight data the was a large voltage drop exactly at the point where it began the death spiral. Most likely because of the shorted windings. But I replaced the ESC along with the motor just to be sure. Luckily for me, it landed almost fully inverted into some deep soft grass. Cracked the shell but otherwise it still flies just like new. Camera and gimbal not even a scratch. I doubt I will ever be that lucky again.

Also, I know of a Phantom that was lost because the e-clip that holds the rotor into the motor came off resulting in the total destruction of that Phantom.

So motors do fail and should be inspected occasionally for anything that might seem abnormal. That is always on the back of my mind now whenever I fly.

 

[taroh]

Guys, please do not confuse "what's possible" and "what happens on P3." If one CW motor stops, then FC tries to keep horizontal, increase power of failed CW motor, decrease opposite side of CW motor. Then theoretically 2 possible ways - if not enough high gain (rapid) to stop turning over, then it flips out. If FC can avoid turning and then decrease surviving CW motor, then CCW wins and strong yaw occurs. If intentional "fail recover" program is not implemented, going which way is decided by sensitivity of each roll+pitch, yaw sensor IMO.
The footage happydays shown, real P3 seems to turn over... But I've ever seen spinning Phantom video (maybe P2), that'll be because not perfect ESC/motor death, or may props broken (partial thrust remaining).
As Morgan shown, prefer spinning may be programmed by designers. ESC/motor/prop failure can be sensed by FC, then enter into "3 motor mode." Spinning in one position is much safer then falling off. If very high speed "home lock mode" is available, an operator can call his poor bird back to the home , but even if not, slow descending may save the bird and people on the ground.

I once opened the body of P2, found one ESC-motor cable was almost broken (bad soldering in factory). Hope DJI programs safe mode in future - don't they currently have that technique for expensive A2 controller? I've ever seen under $100 toy enters into spinning mode when one rotor crashes.

 

[spankybear]

 

[IceFireSoul]

If DJI programs it correctly, it WILL recover from the loss of one rotor (blade, motor). I don't mean you controlling it like it has 4 working props; I am even OK with you not controlling it AT ALL - just the machine falling SLOWER and not turning over; or accelerating in a diagonal towards the earth, hitting whatever.

I think this should be MANDATORY. Currently, even if you DO NOT fly above a crowd; and not above 400 feets... imagine your phantom loosing an engine at 400 feet; above a field. It will have enough travel distance to fly into a zone with people and kill someone. And you you will go to jail. For just watching your phantom killing someone; and while being completely unable to do anything. But again, you put it in the sky, it's your fault.

This is currently a deadly toy. I do fly phantoms for three years, have three of them (1, 2 and 3P); and love them. But am ALWAYS scared "what if".

 

[Meta4]

I think this should be MANDATORY. Currently, even if you DO NOT fly above a crowd; and not above 400 feets... imagine your phantom loosing an engine at 400 feet; above a field. It will have enough travel distance to fly into a zone with people and kill someone. And you you will go to jail. For just watching your phantom killing someone; and while being completely unable to do anything. But again, you put it in the sky, it's your fault.

This is currently a deadly toy. I do fly phantoms for three years, have three of them (1, 2 and 3P); and love them. But am ALWAYS scared "what if".

What if ....?
What if .. it crashes into the open window of a bus, instantly killing the driver, causing the bus full of old folks to crash into a petrol tanker, right outside a kindergarten and shrapnel from the explosion punctures a tanker of toxic waste on a passing train as it's crossing a bridge over the stream that is the town water supply .........
Or another possibility is that it would just come down on the ground somewhere or get stuck in a tree.
The worst-case scenario doesn't always happen.

How many times have you had a Phantom lose a motor in flight?

 

[IceFireSoul]

Never. But still. This has obviously happened to people... And we all want to be responsible, right.

 

[Meta4]

My imaginary case was an example of catastrophising.
Thinking that way, you'd never drive a car or go outdoors.
It's important to consider the likelihood of an event as well as the potential consequences.
eg .. If I buy a lottery ticket, I could win a million dollars !!!
But the chance of that happening is extremely small so I don't get excited about it in advance.

 

[happydays]

What if ....?
What if .. it crashes into the open window of a bus, instantly killing the driver, causing the bus full of old folks to crash into a petrol tanker, right outside a kindergarten and shrapnel from the explosion punctures a tanker of toxic waste on a passing train as it's crossing a bridge over the stream that is the town water supply .........

I think I actually saw that happening one day last week.