It is possible can create the code to use two redundant Fc?
In Italy it is required to approve drones.
redundant Fc?
Re: redundant Fc?
Interesting.
So you would then need a comparator switching unit which would decide which of the two FCs sent the valid outputs and forward only those to the servos and escs? Makes me curious what the terms and conditions are for that unit.
Short answer: no. MWii code does not contain any support for duplicates of anything nor for redundancy.
So you would then need a comparator switching unit which would decide which of the two FCs sent the valid outputs and forward only those to the servos and escs? Makes me curious what the terms and conditions are for that unit.
Short answer: no. MWii code does not contain any support for duplicates of anything nor for redundancy.
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climb4hope
- Posts: 12
- Joined: Mon Jan 27, 2014 11:14 pm
- Location: Seattle, WA
Re: redundant Fc?
I guess there are problems with FC such as code bug that causes infinite loop or RAM corruption that can lead to the reset if watchdog is enabled. We need in the future to be able to recover if the part resets . That might require some extra writes to EEPROM.
On the other hand except the battery circuit failure we might get some other FC failure. Instead of having two circuits doing computation and comparing the data we can add another circuit that does emergency landing only. It can listen the PWM outputs from the primary FC controller in the same way we do listen to RC commands and perform failsafe landing procedures if the PWM outputs fails during the flight. But this is a custom and a long term project. Commercial drones will definitely need some kind of redundancy like that to be able to run motors in emergency case autonomously.
On the other hand except the battery circuit failure we might get some other FC failure. Instead of having two circuits doing computation and comparing the data we can add another circuit that does emergency landing only. It can listen the PWM outputs from the primary FC controller in the same way we do listen to RC commands and perform failsafe landing procedures if the PWM outputs fails during the flight. But this is a custom and a long term project. Commercial drones will definitely need some kind of redundancy like that to be able to run motors in emergency case autonomously.
Re: redundant Fc?
Is such a 2 stage approach considered safe with Italian legislation? It would not convince me as the second stage is your new single point of failure. Unless that piece was proven hardware and software I would consider such setup being even worse wrt.safety than the single FC. Lawyers may think differently?
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Crashpilot1000
- Posts: 631
- Joined: Tue Apr 03, 2012 7:38 pm
Re: redundant Fc?
1. Know the exact specifications required in your country (if they make sense or not, normally legislation rely on "experts", and just by coincidence those specifications may resemble one single product of a major player of that kind in your country...)
2. Design a system for that
3. Get it approved (usually pay $$, come back at least 2 times pay more $$)
4. If you change the software -> re approval (step 3)
Maybe the FS. System designed for the Australian UAV Outbackchallenge could be a starting point for this venture: http://www.millswoodeng.com.au/failsafe_device.html
2. Design a system for that
3. Get it approved (usually pay $$, come back at least 2 times pay more $$)
4. If you change the software -> re approval (step 3)
Maybe the FS. System designed for the Australian UAV Outbackchallenge could be a starting point for this venture: http://www.millswoodeng.com.au/failsafe_device.html
Re: redundant Fc?
Yes, its good idea. MK just have this feature http://m.youtube.com/watch?v=IvrMn4AEAD ... e=m-ch-fea
The redundant only FC is still have high risk the quad fall, need all the component must be redundant.
Most of the problem is motor, EsC and battery in my experience.
Its expensive make redundance FC for just hobby, but there is a good approach to avoid the quad fall down from the sky.
When one of the motor was fail/stop, the quad will automatically :
1. spinning (full left/right yaw)
2. Compass head free.
See this on 6:52 point
http://m.youtube.com/watch?v=w2itwFJCgFQ
Also see this similar scenario
http://m.youtube.com/watch?v=cNdzBRNNkAw
I hope MWI will have this feature
John
The redundant only FC is still have high risk the quad fall, need all the component must be redundant.
Most of the problem is motor, EsC and battery in my experience.
Its expensive make redundance FC for just hobby, but there is a good approach to avoid the quad fall down from the sky.
When one of the motor was fail/stop, the quad will automatically :
1. spinning (full left/right yaw)
2. Compass head free.
See this on 6:52 point
http://m.youtube.com/watch?v=w2itwFJCgFQ
Also see this similar scenario
http://m.youtube.com/watch?v=cNdzBRNNkAw
I hope MWI will have this feature
John
Re: redundant Fc?
Hi all 
I am facing similar problems. Since 2014 in Austria you have to use redundancy in flightcontrollers if you want to make some captures for film, events,...
I am thinking of an additional controller to solve this problem.
If i got it right, multiwii got some nice features to add redundancy. I dont know how often i said it, but i am not a real coder
so this are only theoretical thoughts.
My vision is:
- Take 2 FCs of the exact same kind.
- Add an arduino or whatever mc on the serial ports of both controllers.
- Connect all ESCs/recievers to the additional MC.
- Define Primary controller by adressing the serial ports.
- Let both FCs work as usual
Now we should be able to:
- Check variables like debug for errors (I2C etc.) (We got some nice info if our sensors work)
- Check cycletime (We know if our FC is on the run)
- Check 5/3.3V Power of both FCs (We know if powersource is fine)
- Check if controler is armed, flightmode, number of sats, etc.
- Add a switch on your radio to change FC inflight in case of emergency manually
Our additional MC should now be able to choose the signals from the FC wich is working ok and hand it over to the ESC.
So we got some basic redundancy, right?
I just dont know if this would add too much latency or induce further problems.
I also was thinking of another MC controlling the control MC but this might be too much.
Would be great if you share your thoughts.
Greetz Noc
p.s. @Hamburger
I share your thoughts of inducing new error sources by adding more FCs. But if you want to fly multiwii for creating great captures in austria and a couple of other countrys, what is what i want to do , it has to be kind of redundant, so you get a permission.
I am facing similar problems. Since 2014 in Austria you have to use redundancy in flightcontrollers if you want to make some captures for film, events,...
I am thinking of an additional controller to solve this problem.
If i got it right, multiwii got some nice features to add redundancy. I dont know how often i said it, but i am not a real coder
so this are only theoretical thoughts.My vision is:
- Take 2 FCs of the exact same kind.
- Add an arduino or whatever mc on the serial ports of both controllers.
- Connect all ESCs/recievers to the additional MC.
- Define Primary controller by adressing the serial ports.
- Let both FCs work as usual
Now we should be able to:
- Check variables like debug for errors (I2C etc.) (We got some nice info if our sensors work)
- Check cycletime (We know if our FC is on the run)
- Check 5/3.3V Power of both FCs (We know if powersource is fine)
- Check if controler is armed, flightmode, number of sats, etc.
- Add a switch on your radio to change FC inflight in case of emergency manually
Our additional MC should now be able to choose the signals from the FC wich is working ok and hand it over to the ESC.
So we got some basic redundancy, right?
I just dont know if this would add too much latency or induce further problems.
I also was thinking of another MC controlling the control MC but this might be too much.
Would be great if you share your thoughts.
Greetz Noc
p.s. @Hamburger
I share your thoughts of inducing new error sources by adding more FCs. But if you want to fly multiwii for creating great captures in austria and a couple of other countrys, what is what i want to do
, it has to be kind of redundant, so you get a permission.Re: redundant Fc?
Superimposing two pwm outputs to an esc input should give - chaos. Or nothing working at best.
Your best bet is to read up on the exact requirements. From there do not think about how stupid you may find those but find a way to implement a fulfiling hardware/software solution.
Your best bet is to read up on the exact requirements. From there do not think about how stupid you may find those but find a way to implement a fulfiling hardware/software solution.
Re: redundant Fc?
Reading specs of Pixhawk I see that design has redundant processor so I'm guessing this FC and possibly some other high end units will be the only FCs allowed in these countries.
3DR will be happy & probably lobbied Govt to get this thru
3DR will be happy & probably lobbied Govt to get this thru