I believe he is saying the expo on the Traxxas radios doesnt work very well
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Hobbywing Xerun AXE
- Thread starter Jboucher
- Start date
I believe he is saying the expo on the Traxxas radios doesnt work very well
No, it’s more of an eddy current (switching loss) issue with the revolver. It will spin a lot faster but just start running hot. In that regard, 35krpm is fine too. But 20k is a sweet spot of drivability and efficiency. 14 poles switches a lot per revolution.
Putting expo into the motor controller changes the actual resolution of response, giving more throttle steps at lower throttle. Doing it at the radio does not change low speed resolution, it only makes the radio response feel different. Esc expo is far more effective and predictable when it comes to low speed response.
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mikemcE
I wanna be Dave
Simply put a esc throttle curve is more controllable than an expo curve?
Hang up and Drive
Hang up and Drive
In basic terms, yes.
A radio expo doesn't add extra points to the low speed throttle, it merely stretches out the signal with less information at the first part of the trigger pull. Less twitchy response at low RPM, but not more sensitive. However, adding expo to the ESC throttle curve actually puts more points of control at lower motor RPMs at the expense of upper RPM sensitivity. A typical radio outputs 10 bit resolution, 1024 points of throttle between forward and reverse, 512 points for forward. A normally mapped throttle with an 11v battery is about 0.02v per step. If we put an ESC expo like mine is, the first half of the throttle is remapped to being less than 0.01v per step while the near full throttle gets about 0.04v per step. I've never once thought to myself that I needed more resolution near full throttle, but I've literally been hammering improvements into low end resolution for over a decade between motor and ESC refinements.
To further this concept, there is always a natural order to an electronics system. The motor controls the rig. The ESC controls the motor. The radio controls the ESC. The motor will be the first limit of low end resolution, it must be built to accept fine commands or else no amount of tuning will help. Most motors in the RC market have relatively poor startup by design, since they are borne out of racing and bashing or simply being "cheaply made" for the price point wanted. The ESC must then be tuned to give the "refined" motor fine commands during startup. Finally, the radio can be tuned to help further, if needed. I rarely find it necessary to do anything to the radio when the motor and ESC are properly designed and tuned. The stock TRX radio is pretty junky on the physical throttle, but it does output a steady signal. I did test the startup speeds with a few devices before making the vid to ensure the TRX radio wasn't giving a falsely high startup on the AXE. Nothing could make it better, it is obviously a firmware or hardware limited startup speed.
A radio expo doesn't add extra points to the low speed throttle, it merely stretches out the signal with less information at the first part of the trigger pull. Less twitchy response at low RPM, but not more sensitive. However, adding expo to the ESC throttle curve actually puts more points of control at lower motor RPMs at the expense of upper RPM sensitivity. A typical radio outputs 10 bit resolution, 1024 points of throttle between forward and reverse, 512 points for forward. A normally mapped throttle with an 11v battery is about 0.02v per step. If we put an ESC expo like mine is, the first half of the throttle is remapped to being less than 0.01v per step while the near full throttle gets about 0.04v per step. I've never once thought to myself that I needed more resolution near full throttle, but I've literally been hammering improvements into low end resolution for over a decade between motor and ESC refinements.
To further this concept, there is always a natural order to an electronics system. The motor controls the rig. The ESC controls the motor. The radio controls the ESC. The motor will be the first limit of low end resolution, it must be built to accept fine commands or else no amount of tuning will help. Most motors in the RC market have relatively poor startup by design, since they are borne out of racing and bashing or simply being "cheaply made" for the price point wanted. The ESC must then be tuned to give the "refined" motor fine commands during startup. Finally, the radio can be tuned to help further, if needed. I rarely find it necessary to do anything to the radio when the motor and ESC are properly designed and tuned. The stock TRX radio is pretty junky on the physical throttle, but it does output a steady signal. I did test the startup speeds with a few devices before making the vid to ensure the TRX radio wasn't giving a falsely high startup on the AXE. Nothing could make it better, it is obviously a firmware or hardware limited startup speed.
MaFoDes
Quarry Creeper
Fair is fair.... It is no secret that A'tees is my sponsor (not HW). As it also is no secret that i love my HH products. Raving on the Hobbywing? Not exactly... But i do believe it isn't as bad as it is told here.
Don't get me wrong. I am not picking a fight here. I simply - in all respect - have the opinion that you shouldn't have done this comparison. As interesting as it was!
I am open for all comparisons made. Hell, i love me a good comparison!
Why i didn't come with my negatives? Simple. I have a job that consumes a lot of my time and i am a single dad with 2 kids who want daddytime.
There's only so little time left for rc these days unfortunately. But, yes.. i can be honost on that, i made time for the remarks made earlier.
My biggest con's on the HW are the price. It is way overpriced and i gave that feedback. Being bound to HW motors because of the sensorcable system is another huge con. Even if i also am happy somebody came up with something new.
The internal bec is very, very underpowered. 3A is stone age like....
The FOC has to proove itself. But the future will tell us more.
I will get back on this later!
Acceleration test is up. This was with the fastest programmed acceleration the AXE would allow, faster than the stock setting. I noticed rather serious lag on the rocks when trying to save the AXE rig during rollovers. Softer power delivery than a brushed motor. This prompted me to take it to the pavement to see if I could replicate it there. Hopefully, this shows up well enough in video, maybe listen to the sound if it isn't obvious visually. The AXE rig wont even break traction. The Puller seemed punchiest and was burning out at 30% punch control, but the Revolver was also burning out at 30% punch control so I can't really compare the two castle esc systems fully. Both Castle escs set to highest startup power.
Again, I have to wonder what the purpose of the encoder is when a lower hall sensored AND completely sensorless system is beating it on low speed control and acceleration. Fast positional accuracy and fast acceleration are (supposed to be) the reason that all controllers are not sensorless. Hopefully, they can at least firmware upgrade to improve in these areas.
<iframe width="560" height="315" src="https://www.youtube.com/embed/Lcsz98BLiqI" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
Again, I have to wonder what the purpose of the encoder is when a lower hall sensored AND completely sensorless system is beating it on low speed control and acceleration. Fast positional accuracy and fast acceleration are (supposed to be) the reason that all controllers are not sensorless. Hopefully, they can at least firmware upgrade to improve in these areas.
<iframe width="560" height="315" src="https://www.youtube.com/embed/Lcsz98BLiqI" frameborder="0" allow="autoplay; encrypted-media" allowfullscreen></iframe>
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As I say in the video, I'm probably the pickiest driver in the world and my opinions should be taken with a grain of salt. I'm up front about it. My opinions are strong, but they are also why I know how to make the best crawling motors in the world "thumbsup"
But.. I shouldn't have compared products on the market while sponsored drivers (like yourself) make yes-men reviews that don't seem to put the system through the paces? My day job is literally testing electronics, just like I did on the rocks, and I go home to kids as well. I own a house that is completely devoted to testing RC crawlers and making videos. In all likelyhood, nobody else is going to step up and put the effort (and money) into it like I have done. Maybe somebody will, I hope there are more reviews done with more than just parroting the specs from the HW website and then showing it crawl over some little roots or something.
I hope that hobbywing can heed my review and make improvements quickly. Otherwise, they are going to release a product that doesn't meet anything in the market on performance. It will be like the "novak" crawler systems were.
cartronicshn
I wanna be Dave
Yes i was there
, remember the first goats?
I for one really appreciate the review JRH has provided. I knew nothing about this AXE setup but knew that John would explain it in a manner which I could grasp easily, which he did (Thanks).
As for a Bias, on paper yeah he should be, but in practice I'm not seeing it. Bias implies that something was favored in an unfair manner, and that I'm not seeing either.
As for a Bias, on paper yeah he should be, but in practice I'm not seeing it. Bias implies that something was favored in an unfair manner, and that I'm not seeing either.
Holmes is the only one of us that has the capability of doing what was done.
He has all these different systems to test. I know I dont have that just laying around.
He cant be biased when it just shows that it isnt better than the others.
He has all these different systems to test. I know I dont have that just laying around.
He cant be biased when it just shows that it isnt better than the others.
Stargate360
Newbie
I have read all this thread and my conclusion is that we have to give a chance to this combo. Nothing is perfect when first released. We have to remember when Castle jumped into HV. Their air esc was burning down at an alarming rate. That has almost put the company in jeopardy. We used to call them Castle Cremation.
Would have been nice to see the HH test made between this HW combo, the Mamba X Crawler Edition combo and a Trail Master BLE Pro/Puller Pro BL combo. Going mix matched esc and motor is irrelevant to me.
As for the Intelligent Torque Output & Speed Closed-loop Control, it's just a matter of learning how the system works and my driving will adapt to it.
For the sensor harness, I'd rather see something like this than the always breaking and almost impossible to waterproof 6/1 connector. Speaking of waterproofing, HW is the first company that I see claiming an IP67 rating on a crawler combo. Only time will tell if it's true or not.
Having a proprietary motor is not a problem for me if it fill the bill for my needs and is up to the task. HW will surely make the motor or the esc available as replacement parts.
Would have been nice to see the HH test made between this HW combo, the Mamba X Crawler Edition combo and a Trail Master BLE Pro/Puller Pro BL combo. Going mix matched esc and motor is irrelevant to me.
As for the Intelligent Torque Output & Speed Closed-loop Control, it's just a matter of learning how the system works and my driving will adapt to it.
For the sensor harness, I'd rather see something like this than the always breaking and almost impossible to waterproof 6/1 connector. Speaking of waterproofing, HW is the first company that I see claiming an IP67 rating on a crawler combo. Only time will tell if it's true or not.
Having a proprietary motor is not a problem for me if it fill the bill for my needs and is up to the task. HW will surely make the motor or the esc available as replacement parts.
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Typos in the highlighted sentences?
I believe you meant HW (HobbyWing), not HH (Holmes Hobbies)...
And they are selling the motors and ESC separately already.
My thoughts regarding his leaving the HH Trailmaster BLE Pro out of the test were mentioned before - it's a generation behind the new CC Mamba X.
Stargate360
Newbie
Typo fixed. I meant HobbyWing.
Nice to know motors and ESC available separately.
Nice to know motors and ESC available separately.
Topher Builds
I wanna be Dave
JRH is doing legitimate bench and field tests, it seems what you provided is nothing more than commentary on the released specs. I’m impartial and have no plans or needs to change any electronics; JRH has given a heck of a lot of helpful info and examples whereas all I’ve seen from your post is a summary of takeaways on the message board from others speculating over the specs.
I get what you’re saying in theory, if Pepsi is telling me Coke sucks because it isn’t Pepsi then that’s one thing, but JRH did much more than that.
Perhaps firmware updates will clear up some of the low speed resolution and throttle control and we’ll see another updated test from JRH.
https://youtu.be/Lcsz98BLiqI
Another vid from holmes
Another vid from holmes
MSH
Pebble Pounder
I think they need to make this system with the option of normal throttle control.
svt923
I wanna be Dave
Exactly
The XeRun XR8 sct is already pretty badass, it's missing the waterproof and tweaks for crawlers.
They could have made a new version with the new sensor cable and adapted the G2 motors.
Or even better, make an AXE-light system without Bluetooth, add a regular driving style and drop the price.
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