05-30-2018, 02:34 PM | #221 |
Quarry Creeper Join Date: Jun 2016 Location: Tacoma
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| Re: Hobbywing Xerun AXE |
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05-30-2018, 02:55 PM | #222 |
Rock Crawler Join Date: May 2018 Location: USA
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| Re: Hobbywing Xerun AXE |
05-30-2018, 03:18 PM | #223 |
RCC Addict Join Date: Feb 2017 Location: Surprise
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| Re: Hobbywing Xerun AXE
It's in a rig in this vid https://youtu.be/0IMZCzZC8vs EDIT.... Warning he gets a lil hot N heavy at the end ! Lol Last edited by Frank211; 05-30-2018 at 03:27 PM. |
05-30-2018, 03:21 PM | #224 | |
Rock Crawler Join Date: May 2018 Location: USA
Posts: 792
| Re: Hobbywing Xerun AXE Quote:
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05-30-2018, 03:35 PM | #225 |
owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down!
Posts: 20,290
| Re: Hobbywing Xerun AXE
I've done a few more hours of both bench testing and crawling today. Tomorrow I will do the same and record it on video. It seems that it might be a basic implementation of closed loop (crude) FOC via lookup table and the encoder, the same implementation that encoder steppers (servo drive) uses. The sine wave approximation is very poor though, so I had dismissed it as simply trap drive earlier. They seemingly did a poor job at matching the motor bEMF. But there is activation of all three phases at the same time, and this is a mark of FOC. I'll hold off on the pitchforks and torches in regards to FOC claims, ha! But I can restate that this is not a good approximation of a sine wave, and that is an important point of efficiently FOCing a motor with sine bEMF. This also hammers in that there is little chance that other motors are compatible. So this is by no means a universal ESC, but a system where you will only have a few choices of motor. On the rocks, it drove as anticipated. It was relatively consistent in speed during load changes, but still had some "loading" evident during big changes. Not a marked difference to how a mamba X drives and downhills though. The torque application was quite unruly, however. I got sucked into a crack at just a hair of throttle and flipped the rig with little warning. The minimum startup speed when loaded seemed the same as unloaded startup speed, although it seemed smooth enough for the average driver. This is a difference to the Mamba X or BLE, where getting up to an object lets the motor load down and butter through at a lower startup RPM than the simply unloaded RPM. I'll have more time to test this tomorrow and will report back. I think the system may have fans of how it drives, but I've come to love and expect "normal" PWM throttle response. It's literally engrained into my throttle finger and brain, so learning this as precise as I've learned to control PWM throttle would take a lot of time watching the tire shape. The tire noise and deflection seemed to be my only feedback to load. Lots of head scratching and Hmmmmms today. |
05-30-2018, 03:36 PM | #226 | |
RCC Addict Join Date: Feb 2016 Location: Princeton, North Carolina, USA
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| Re: Hobbywing Xerun AXE Quote:
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05-30-2018, 03:40 PM | #227 |
owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down!
Posts: 20,290
| Re: Hobbywing Xerun AXE
O scope output. Notice the sharp transitions from low duty to high duty on each phase. Or not, maybe you don’t look at these things as much as I do, lol!
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05-30-2018, 03:43 PM | #228 |
owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down!
Posts: 20,290
| Re: Hobbywing Xerun AXE
A little more zoomed in. Each phase rides at peak duty a looooong time per commutation cycle. There is a little slope to the area under the curve, but still not nearly sine approximation.
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05-30-2018, 03:46 PM | #229 |
RCC Addict Join Date: Feb 2017 Location: Surprise
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| Re: Hobbywing Xerun AXE |
05-30-2018, 04:21 PM | #230 |
Rock Crawler Join Date: May 2018 Location: USA
Posts: 792
| Re: Hobbywing Xerun AXE I see what you mean, thats not sine at all. If you hadnt told me Id say it was just a normal 3 phase digital motor.
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05-30-2018, 04:46 PM | #231 |
owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down!
Posts: 20,290
| Re: Hobbywing Xerun AXE
My calculations show it is a trap waveform with 1/3 of the time rising and falling. 1/6 rising duty, 1/6 falling duty
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05-30-2018, 04:49 PM | #232 |
RCC Addict Join Date: Jun 2017 Location: Canada
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| Re: Hobbywing Xerun AXE
This thread might as well be written in Klingon by now, i feel lost among supreme beings... Sent from my Nexus 6 using Tapatalk |
05-30-2018, 05:27 PM | #233 |
owner, Holmes Hobbies LLC Join Date: Nov 2004 Location: Volt up! Gear down!
Posts: 20,290
| Re: Hobbywing Xerun AXE
Don’t worry, I’ll speak more touchy feely stuff tomorrow. I just like balancing opinions of feel with some hard measurement and theory.
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05-30-2018, 05:40 PM | #234 |
Rock Crawler Join Date: Nov 2014 Location: Dells
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| Re: Hobbywing Xerun AXE
wrong thread
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05-30-2018, 06:00 PM | #235 |
Moderator Join Date: Sep 2008 Location: PA
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| Re: Hobbywing Xerun AXE |
05-30-2018, 06:13 PM | #236 | |
RCC Addict Join Date: Nov 2016 Location: 1972 born Christian, Chinese.
Posts: 1,321
| Re: Hobbywing Xerun AXE Quote:
Any chances to know what gearings are in this testing? ( Spur and pinion ) | |
05-30-2018, 06:26 PM | #237 |
I wanna be Dave Join Date: Jun 2016 Location: Austin
Posts: 6,013
| Re: Hobbywing Xerun AXE
That's why actual side-by-side comparison reports are going to be so important - it's all fine and dandy if it crawls at a snail's pace with a certain amount of control... But how is it throughout the entire rpm range? Is there a reason that it's being advertised so much paired with relatively low-kv motors, when it won't take more than 3S? Some listings do now show a 3300kv, but I am very interested in more hands-on driving information when there's no rep handing someone the controls of a "mystery" rig. Knowing how it's geared and then how well it runs at a slow crawl, then handles bursts of power to get out of a stuck situation, and finally some throttle-pegged results. (rubs hands together in anticipation...) |
05-30-2018, 10:42 PM | #238 |
Rock Crawler Join Date: May 2018 Location: USA
Posts: 792
| Re: Hobbywing Xerun AXE They arent claiming that its the same as everything else, they are CLEARLY saying that its the best thing on the market, never before seen! Watch / read all the promotional stuff. I get that you accept lying in marketing as inescapable but in most peoples eyes that is not a valid excuse. If they were saying they were just as good as the competition no one would be complaining. They are claiming to have created the best thing since sliced bread.
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05-30-2018, 10:43 PM | #239 | |
Rock Crawler Join Date: May 2018 Location: USA
Posts: 792
| Re: Hobbywing Xerun AXE Quote:
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05-30-2018, 10:45 PM | #240 |
Rock Crawler Join Date: May 2018 Location: USA
Posts: 792
| Re: Hobbywing Xerun AXE Meh, I bet if you started talking to me about your industry I would feel just as lost. So far John hasnt even talked about too super advanced electronics concepts, and thats from a man who quite literally makes his living making and selling motors, servos, and controllers.
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