Hi there!
Legitimate 3DR Pixhawk owner.
I started my first Pixhawk build 3 days ago with SimonK Afros. No go. Sync issues, even after FW update.
Bought and overnighted some EMAX 60a ESCS. Apparently EMAX also has compatibility issues with Pixhawk.
No go, for whatever reason, and the dev ticket to fix this issue is apparently closed with no solution.
What's a not garbage 40-60a ESC that isn't terrible that I can go spend even more hundreds of dollars on that is guaranteed to work with the Pixhawk?
Rules:
No SimonK, because that firmware isn't compatible.
No EMAX because that hardware isn't compatible.
I hope this could end up being an actual, no BS compatible ESC reference for others that have less time or cash they want to waste
Replies
Given all he has contributed, I would be an even happier 3DR customer to know they'd sent a Pixhawk Simon's way
Did SimonK literally just hit my thread up. Neat.
So because I think I'm special and love Afros, I decided to build with Afros despite Marco Robustini's clear warning to not use SimonK firmware with Pixhawk, with a nice demo of an esc losing sync and exploding.
I didn't get an explosion, but after one motor lost sync in the air it was followed by all others losing sync shortly after because of, I am guessing, the crazy high variation in loop output to the ESCs. Dropped out of the sky, but luckily I was hovering at around 4 feet. MP logs indicate beautifully linear and coreographed failure of all ESCs within about 3 seconds of one another.
All of my ESC cabling was installed with some EMI foil, and EMI foil was additionally used to back my acrylic canopy. I do totally understand that shielding EMI is a fine art that is not as simple as wrapping stuff in foil, but I went in with the desire to ensure the only reason my craft crashed is because of something I did.
I later tried with some ferrite rings I stole from some other dead electronics, but I am beginning to think perhaps the ESC firmware is maybe discarding the last control loop and pole sensor data when it gets a vastly different new one (this is substantiated in no way, merely uneducated speculation).
I decided to go to some EMAX units running BLHeli, but I later found out directly from EMAX that NO EMAX ESCs work with the pixhawk, I am guessing due to a high variation in expected PWM input voltage by the ESC and the actual PWM voltage output by the pixhawk. It's funny that 3DR never mentions that what I see as the best designed ESC hardware just doesn't work, and obviously some of the best designed ESC firmware also doesn't work. At least SimonK incompatibility is mentioned in some setup Wikis.
I did notice that in very calm flight that required little variation in control loop output, the SimonK Afros were fine, but my motors got way warm, even when just hovering, and I was getting substantially lower flight time than I should have given my weight and calculated g/w of 11/1. After a 4 or so minute hover, I found my motors operating at around 105F, on a cool day. I found this to be abnormal amounts of heat, and I think this was caused by perhaps actual pole position versus sensed pole position in the ESC, and some timing issue that rose from that.
My motors never sounded normal running the SimonK ESCs with (well balanced) props on, and I attributed it to other vibration until I had full blown sync issues, and connected the unusually warm motors with inefficiency derived from slightly off timing. Props off and unloaded, they functioned very well. I did make a crappy dyno with a DC motor and once I put about a consistent 45 watt load on the motors, they did exhibit some desync with SimonK.
I overnighted some T-Motor Air 40a ESCs, hopefully my issues are gone after I install those.
Hi Phil,
The ESC always uses the input immediately following the low-going edge, unless the pulse is of an invalid length (too short or long).
Note that the EMAX units just borrowed my name for marketing but have nothing to do with me. They've never shipped my code as far as I know.
You say your motors ran hot and sounded weird. Which motors, props, and voltage? How long ago did you buy the Afros, and did you try a firmware update?
Simon-
The Afros were purchased from HK a little over 3 weeks ago. Props are 14x4.7 carbon fiber, motors are HK Multistar Elite 4006. I am running 4s true Lithium Polymer.
I did try a firmware update to the latest a few days ago and was not able to reproduce the issue on the bench, but I did not take it to the air because I did not want to run the risk of harming property or persons nearby.
I installed new T-Motor Air 40a ESCs and tested them in flight today and found them to have outstanding performance. These ESCs appear to be rebranded Hobbywing XRotors, I am unsure of the firmware, but out of the box they were stellar.
The motors after 15 minute hover came around 80f from 75f ambient temp, and ran noticeably quieter. Flight time increased as well, on the same battery.
Note possibly related issue: https://github.com/sim-/tgy/issues/50#issuecomment-68303939
I've been using Afro 30 Amp ESC's with SimonK as shipped from HK for a year on my 3DR Pixhawk with no problems. The motors are Sunnysky V series 2814 KV800 and the props are APC 12x4.5 on a 680 class frame using 4S batteries.
The warning was more directed at lower KV/High pole count motors. Mine are 24 pole, those 2814s are likely 12
Yep, true. You might want to qualify your "neither work with Pixhawk" claim above to reflect what you really mean.
You're right. I was a little butthurt about the lack of documentation and dismissal by the dev team when literally the best stuff ever doesn't work with applications that require big motors.
2 years and no hardware or software update that solves these actually big issues, and no CANbus driven ESCs or even Oneshot compatibility.
Phill,
Have you read through this thread: http://diydrones.com/forum/topics/simonk-firmware-motor-sync-proble...
I briefly thought I would try low KV motors for my build but found that the KV800's worked for many other people on the 680 so I didn't pursue this any more.
There are quite a few problems you can eliminate since the Afro's work for others:
So that leaves the timing parameters used in the SimonK firmware or the firmware itself. I've seen posts by Simon and others on how to change the timing and recompile the firmware and I've also seen posts recommending a switch to BLHeliSuite which you can load onto the Afro.
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