Motor Failure
- Thread starter Cheshirecat
- Start date
What a strange statement.
The Herk board was the only board that the likes of Kopterworx used not so long ago, (they are probably professionals) the only reason why you don't see it as much is that they are lifting massive weights now which you simply can not do with the Herk as it is only rated for 30A / motor, so lifting an ARRI may be a bit out of its capabilities.
R_Lefebvre
Arducopter Developer
Great argument... love your science, dude
But it's not that much different than "it's expensive, so it must be good".
R_Lefebvre
Arducopter Developer
If it didn't hold in GPS mode, but was able to in manual mode, then it would seem like the programming or tuning of the WKM was the cause. Because obviously there was physically enough thrust. I'd suspect the Yaw I-term could not grow big enough. But that's just a guess.
But it's not that much different than "it's expensive, so it must be good".
I don't think I used that argument...
R_Lefebvre
Arducopter Developer
I didn't say you did, but it's a common argument, and I believe it's been used in regards to the Herkules. I'm just pointing out that there's a lot of anti-science in this industry.
Old Man
Active Member
Of greater issue than a single Herk board or independent ESC's is the power distribution boards we use. Consider that out primary power outputs are all solder joints of one type or another. Solder is fragile and will not indefinately hold up in a high vibration environment. When the solder terminates inside wire insulation is a natural brittle point in the wire and a well noted failure point in all things that have wire solder joints. We need a well engineer re-design of our PDB's that eliminate solder requirements, be they bullet connectors or direct soldering to the board. Some relatively simple mechanical modifications to a much lighter version of a Power Hungry board would do the trick.
Rob L.,
I hope you're listening since you have an M.E. background. I had an idea for this some months ago I gave to a fledgling engineering company but as soon as they drew a Solidworks (v2005) drawing of my design, and afterwards wanted to charge me $5k to have the drawing. I walked away from it. They never bothered to do anything with it themselves.
Rob L.,
I hope you're listening since you have an M.E. background. I had an idea for this some months ago I gave to a fledgling engineering company but as soon as they drew a Solidworks (v2005) drawing of my design, and afterwards wanted to charge me $5k to have the drawing. I walked away from it. They never bothered to do anything with it themselves.
Wow, now this is the thing.. I have not been at this long, but after a year and a half I do NOT know who to believe.
I have heard some very smart people say that a solder joint is the only way to go. @FerdinandK
I have learnt during that time not to believe everything I read online.
Now I do not know who to believe, one minute I hear one thing, next minute its the opposite..this drives me crazy, too many experts but who do you listen to?
Surely there are always solder joints at some points, after all how do you connect the bullets?
Cheshirecat
Member
Well i know exactly what the issue is with the Herk, and it aint the Herk itself.
The problem is the Micro Match connectors which are clearly just not crimped properly, they are supplied loose and i thought i had crimped them properly (spent some time inspecting them as well) but not the case, i can replicate the drop outs by wiggling the cable around with the motors running on the test bench and after considerable wiggling a motor stops for a few seconds and the data logger logs motor status 480.000 which is a PPM control signal disconnect.
it would seem the Micro-match connectors need specialist tools so i will hunt down pre professionally terminated ribbon cables i think.
Unfortunately i had to cancel my assessment, not doing that until i know it is 100% and fortunately Resource UAS were brilliant about it.
The problem is the Micro Match connectors which are clearly just not crimped properly, they are supplied loose and i thought i had crimped them properly (spent some time inspecting them as well) but not the case, i can replicate the drop outs by wiggling the cable around with the motors running on the test bench and after considerable wiggling a motor stops for a few seconds and the data logger logs motor status 480.000 which is a PPM control signal disconnect.
it would seem the Micro-match connectors need specialist tools so i will hunt down pre professionally terminated ribbon cables i think.
Unfortunately i had to cancel my assessment, not doing that until i know it is 100% and fortunately Resource UAS were brilliant about it.
Old Man
Active Member
Take a look at FAA standards for aircraft electronics to determine the safety level of solder joints. As for bullets, you should not use them. Crimped connectors and twist locks (canon plugs) are the preferred aviation safety standard. Bayonet/slide mounts are also considered in the safe category if going board to board. Yea, @FerdinandK does some truly great stuff but he's not flying anything a life is dependent on. At least until he flies over people's heads.
BTW, another real crappy connector is the JST. It's one of the most corrosion prone connectors you can buy, especially when not gold plated. Great for your home desk top and other IT uses though. It's amazing that our primary connection choices are some of the worst that are available. They are among the cheapest though. I'm certain all of this will be corrected when the FAA finally dumps their airworthiness standards upon us. They've pretty much already made it plain they will be extending the current certification process to anything we want to fly commercially.
BTW, another real crappy connector is the JST. It's one of the most corrosion prone connectors you can buy, especially when not gold plated. Great for your home desk top and other IT uses though. It's amazing that our primary connection choices are some of the worst that are available. They are among the cheapest though. I'm certain all of this will be corrected when the FAA finally dumps their airworthiness standards upon us. They've pretty much already made it plain they will be extending the current certification process to anything we want to fly commercially.
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Cheshirecat
Member
Yes i agree 100% Quinton, in a way it was a good experience (emphasis on experience) i will always be better prepared for future failures and will add a whole new level of rigorous bench testing from now on, that's the positive i am taking away from this.
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Cheshirecat
Member
Most of the connectors i have seen used in the RC world are of a fairly sloppy standard, from Servo connectors to battery plugs.
It will be interesting in all ways to see what the Civil Aviation Authority come up with now they have introduced an airworthiness certification process for >7Kg MR's from October. I wouldn't be surprised if it includes redundancy all the way back to and including the Flight Controller.
It will be interesting in all ways to see what the Civil Aviation Authority come up with now they have introduced an airworthiness certification process for >7Kg MR's from October. I wouldn't be surprised if it includes redundancy all the way back to and including the Flight Controller.
fltundra
Member
Follow the Nasa guidelines on soldering or crimp connections, and it's not an issue.
http://workmanship.nasa.gov/lib/insp/2 books/frameset.html
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JST connectors are THE crap.
As for FAA standards, we aren't flying full size planes/helicopters. Or even full size 'drones', so they need to sit back and relax. They can simply take a look over the pound to see how every other country is doing it, and has been for a few years. Voila done, save the million of dollars of bull**** 'research'.
None of this even addresses the primary issue: Clueless people with $500-$1000 to spare to buy a off the shelf quad and fly it over densely populated residential area's, into buildings, near airports, etc.
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This is the bit that threw me
I worked as a CNC engineer years ago that made ejector seats for Martin Baker, a lot of the stuff I read in these forums I take with a pinch of salt.
I am fully qualified to fly commercially here in the UK, (one of the few countries that has got their act together) but its nothing to do with how good your machine is, its based on if you are capable of flying or not.
We still have a long way to go, regarding simple things like connectors.
This is the bit that threw me
I worked as a CNC engineer years ago that made ejector seats for Martin Baker, a lot of the stuff I read in these forums I take with a pinch of salt.
I am fully qualified to fly commercially here in the UK, (one of the few countries that has got their act together) but its nothing to do with how good your machine is, its based on if you are capable of flying or not.
We still have a long way to go, regarding simple things like connectors.
That is how it should be. Some regulation over the parts we use i can understand, i don't want to see 10kg UAV's made of cardboard and tape holding a 1.5kg camera over my head... lol
Weed out the clear idiots that have NO IDEA what they are doing. Mostly make sure certified people have the proper knowledge/insurance.
fltundra
Member
Hence the reason pilots license required, that alone is going to weed out many.:tennis: