Trying to Decode the Secrets of the Losi PromotoMX Gyro!
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- เผยแพร่เมื่อ 8 ก.ค. 2024
- Part 2! My last video my original hypothesis as to how the Gyro assisted the @losiracing #promotomx has been proven wrong by Spektrum themselves! I take a closer look on the bench and I think I might have figured out the secret sauce! Check it out!
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Chapters:
0:00 Intro
1:16 Response from Spektrum/Losi!
2:30 About the Gyro
8:03 Methodology
9:27 Bench Testing & Discussion
19:08 MAKE SURE YOU WATCH THIS PART
21:55 Closing Thoughts & Outtro
Tags: #rc #rccar #rccars #rctruck #rctrucks #radiocontrol #losi #losiinspired #promotomx #losipromotomx #rcmotorcycle #dirtbike #motocross #analysis #testing - บันเทิง
This is a great video. From my analysis they are effectivey using their SAFE technology from the AS3X air receivers. This (SAFE) is what John referred to as angle mode - when you steer the bike it is commanding a lean angle, and the gyro controls the steering servo to maintain it (within what it can achieve for a given speed). I will use the term stick to reflect an air transmitter's inputs (rather than wheel/throttle). I have many years of programming their AR636 plane gyros, including editing the raw configuration files, given Spektrum never actually provided a tool for adjusting a lot of these paramaters.
Coupled with this base observation, there are other elements of AS3X which are worth understanding.
1. Heading hold. It is clear when observing the steering servo that it is not just correcting for temporary changes in direction, but it will continue to make that correction until it restores the desired heading. This is obvious when the bike is stationary on its side and the steering servo goes full lock as it attempts to correct for the accumultated heading error. Note that heading hold typically only operates when the stick is centred.
2. Stick priority. Stick prioriy effectively turns down the gyro gains as the stick travel increases. Effectively the gyro is at its highest gain at centre stick - a higher stick prority reduces gains quicker as stick inputs increase.
3. Gain control. This is what the MS6X knob adjusts, and for my 2c, is the biggest flaw in the RTR setup. When you are adjusting that knob it is clearly adjusting (at a minimum!) gyro gains AND angle limits, and not necissarily in a way that we as riders want. For example, i would like to reduce gyro rate gains (to make the bike less wobbly as the steering gyro over compensates in certain conditions - in planes we would call this oscillation) WITHOUT reducing bank angle limit, and without reducing the permitted wheelie angle (because reduced wheelie angle limits can also affect the bikes performance over jumps, resulting in nasty crashes if it cuts throttle at the wrong time). Ideally they would allow, even if it meant buying a DX5, independent adjustment of various gyro gains - or better yet, expose these settings through a programming interface and allow us to adjust them to our needs.
What is less clear to me, and where they are doing something different, is as it relates to the throttle channel. It could very well be as simple as pitch angle limits, which chops the throttle once a given pitch angle limit is reached, but i would expect that to behave slightly different at lower throttle rates.
Spektrum being spektrum, they are unlikely to expose a lot of these settings for us to play with (doing so could also inadvertantly draw back the curtain on just how complex it is - or is not). If you connect the receiver to the spektrum programmer software, there are absolutey zero settings which are visible - the only function it offers is registration and updating firmware.
The patent documentation is hopefully informative. If you havent found it already, there is a manual for the receiver floating around online, which suggests that AUX 1 and AUX 2 channels can be used to adjust steering and throttle gains indpendently. I suspect the MS6X knob is simply adjusting these aux channels at the same time.
Note that 6 axis is a bit of a misnomer, unless spektrum are also correcting for errors on the space-time continuum. The accelerometer data improves the accuracy of the gyro's ability to detect what is going on, which no doubt improves the responsiveness of the gyro and the driving/riding/flying experience, but should effectively be transparent when it comes to tuning the gyro through various heading hold/rate/angle limit settings.
This is great additional context! Ive driven this bike quite a bit more since I made this video and I always run this thing at minimum/zero gyro input now. In dirt mode I feel more and more like the only thing Im really adjusting with the lean knob is how much throttle the gyro will limit me to using. Everything else really seems the same other than how much throttle it chops from you with max assistance. Ive yet to find a scenario where turning the gyro input up has been beneficial for me, even in tighter situations since Id rather be able to steer using the throttle and at max lean/gyro input I feel like the bike is just being held back so much. I can recreate the lesser lean angle simply by using less throttle input and get the same effect.
I honestly kind of think of it almost like a training mode now. Unless I make some new discovery around how it operates it seems like if someone is driving it who never has, you crank the assist up so they dont dump it in a corner, as as you get better you give them full control over the throttle (on top of going from 50% throttle limit to 100% over time on the transmitter).
Ill be interested to see two more things, which ill make some vids about when I get the parts, and thats A - does the street mode operate the same way (need my street tires still) and B - If I can sus out any more insight in dirt mode with street tires on on pavement where I can eliminate some of the randomness in my testing caused by un-even terrain. Ive got a local skate park with a great bowl to test some banked corner behavior too so Ill be all over that as soon as I get my rear supermoto tire in.
@@NHO-RC Yeah there is obviously a mechanicl element to all of this right - in that the speed of the bike also affects the achievable lean angle. I have subscribed and look forward to your further analysis!
Thanks!
My first time driving my Yamaha colored MX it was on a baseball field. I ran two battery packs about 20 minutes of riding time. I had my lean at 25%. I think it handled very well. I only did one upgrade and that was a new GPM front caliper. I never had to do a walk of shame. I think this thing handles incredible. It’s just gonna take a little bit of practice and working the brakes and throttle in the corners. That was in dirt mode my go to for control.
Awesome video for some insight to how it works. I do believe for the wheelie mode its controlled by the tx/rx. If you take the tx/rx out & install into a rc rig that will do wheelies (drag car) depending how you have the rx orientented in the rc chassis it will allow more or less wheelie action. 6 axis Gyro really only helps keep bike upright.
Thanks for doing this style video…
I too am very interested in how the tech side works and how we tune it for racing conditions.
Keep up the good work!
Thank you for the kind words! Ill keep at it till I figure it out!
Thanks for video. It help me out. Love mine. So much fun
Thanks happy to help!
Just enjoy the bike It does what it's supposed to do some things are better unknown. Too many copycat manufacturers in the game.
Best I could do is 12:00 on the lean knob for dirt.. using blips on the throttle in the turn
and adjusting corner speed ( the hardest part).
You should ask them to give us access to tuning the PID loop.
I was hesitant on this and even first time I drove it. But I just keep wanting to drive it and you don’t need to go 70mph to have fun with this. I have had and sold almost every newer rc car and truck and this is not the fastest one but the most fun.
It's amazingly fun! I don't understand the people who push this thing to 70! It's an amazing rig!
Very interesting 👍🏻
Glad you think so!
@@NHO-RC The gyro in this bike is pretty much like the Spectrum SAFE technology I have in all my planes, You can be upside down and loose orientation and flip it into SAFE mode and the plane will automatically find the fastest way to level it's self with out zero input to the sticks, it has saved many of my planes from the RC graveyard - trashcan 😂🤣 That's so awesome how they programmed the gyro for this bike to control the wheelies etc etc etc lol Fricn mind blowing and way above my technical abilities which is pretty much zero 🤣 I'm all for learning more about how it works though 👍🏻
So they came out with an uodate so you can use the dx5c or dx5r transmitter, the only problem is you loose all other saved models when you do the update.nor sure weather i want to reprogram 8 models at this point.
It is nice of you to commend the Losi people maybe they will enlighten all of us on pg 11 of the manual it mentions that the run time is 9-12 minutes ( which in my opinion is very very low) the Horizon rep I spoke to even in email stated in print that after that run you all recommend letting it cool for 5-10 minutes before running it again - this has got to be worst case sensation -$550 bucks for runs of 9-12 minutes WOW
Ive certainly gotten some 9-12 minute run times if I am really running the thing full throttle with no stops. Under more realistic bashing conditions I think 15-20 is more realistic if you are going a bit slower which is nice. As far as cooling, Im not sure how hot the motor gets, but the flywheel really heats up. As soon as a company releases a aluminum skid plate that will really help suck heat out of the flywheel.
@@NHO-RC I would think Losi creators would have thought of an aluminum skip plate already-Hey what kind of battery are you using please send link
Im wondering if it wasnt done because it gets too hot to touch which could be a liability. The plastic plate gets hot enough that its uncomfortable to touch sometimes. I am running the recommended Losi batteries in both 50c and 100c variants. - www.losi.com/product/7.4v-5000mah-2s-100c-smart-g2-hardcase-lipo-battery-ic5/SPMX52S100H5.html
I 💬 nk this would make more sense with a box style transmitter. That way you could possible map the yaw input to maybe the ride weight. Without being able to control the rider it is never going to function correctly at slow speeds & high speeds cornering
Yes it has its limits at the low end since the rider can't move. Don't see any easy way around that unfortunatley
Hey Man, just some food for thought coming from someone that has been in the hobby for over 40 years and could write a book on gyros, PID's, axis priority qnd accelerometers. I picked up one of these 2 weeks ago and I the 1st thing I did was try and analyze the the entire gyro system both mechanical and electronic. I would agree with some of your options but not all. And please let Losi recoup at least some of their tooling costs before you figure out the" hidden secret " so some clown engineer in China can ignore a US patent and try and sell us crap that ruins our hobby.
version 2 please, send that back.
What do you mean?
Great Video love the info,,,, I do speed runs, I need to know how to get rid of the Steering Wobble at high speed, i think the gyro is causing the Death wobble. Any suggestion NHO-RC ?
Generally you get the death wobble when you have the lean knob gain too high. The system over corrects far too much for high speed. This happens on most RCs that have normal gyro like an XMAXX that help it go straight turned up way too much. Try turning your lean knob down a bit when you are doing high speed passes and see if this helps. You really dont need any Gyro on this thing at high speed in a straight line as the flywheel really helps it stay straight. Its a tradeoff of how much gyro you want vs not getting death wobble at high speeds.
I appreciate the advice...thanks so much. I will turn it all the way down. I'm at 75mph now.
75???? How did you get it moving that fast? 3S conversion?
@@NHO-RC change gears, and I run a Castle esc and motor combo.
2FM RC... excellent how it works videos.
Ill check it out!
Has he put one out on the Gyro? I only see ones about brakes and first runs ect.
He has not. His vid with the program card, killer info.
I'm in Brazil on Aliexpress 3800 reais apart from shipping there in the USA how much do you pay there in reais or dollars?
600 with battery and charger 550 without.
@@NHO-RC Could you translate what you sent 🙏
no change speed of wheel gyro , very slow response
Losi needs to have there videos on there products. It's new, but is like the possi track in a 72 dart ? Nobody nows how it works, it just does ?
I agree, they have done a generally great job with explaining how most other parts of this work with their launch here between YT vids and Social media posts but this has still been left out! I gotta know!
I'm a old bike wrench, and losi is real close to scale mechanics on the mx. Like you, I think knowing the sweat spot, then fine tune it to your exact conditions. Believe me on this, it's a complex machine. Wait till tomorrow, even better.
🙂👌👍
Do you ride motorcycles? I think riding one may better your understanding of what’s going on here
I do but I am the gyro so it doesn't really help understand what exactly the lean knob does
@@NHO-RC I’ve not got my hands on a PromotoMX, but my immediate impression from watching content was that outside of wheelie mode that knob is limiting / controlling the amount of countersteer alongside taking over a bit of your throttle inout to control lean angle
I’m always amazed at how much throttle inputs change lines when cornering on bikes
Great vid. Glad somebody is as curious as you ad to what’s going on here 👍🏼
Thanks! Yeah from what I can tell the change to the steering inputs is far less drastic from one side of the lean knob to the other, it seems mostly to restrict your throttle aggressively at the zero lean setting though.
The part that is really confusing me is that on a real motorcycle, or even a pushbike - at slow speeds you turn the bars to the left to turn left. However over around 10 mph this is reversed and we deal with it naturally. Countersteering is very difficult to explain even to seasoned bikers as we just do it without really understanding the physics at play in many cases
I think the Losi has the steering reversed even at slow speeds though. Looking forward to seeing if the Losi technician provides any intel here
@@NHO-RC the plot thickens! I’m in the UK and think it will be a while until I can get my hands on one. Will follow your content with keen interest
(I think Yaw isnt used), it work excactly like a plane Aileron (autolevel) , I have transforme my SR5 with 6axes Gyro plane to have same fonction, (not whelly more complex,) : th-cam.com/video/JdNyC_psKQ8/w-d-xo.html
I'd like to see how it rides without the rider. You can be the first that I've seen.
👀🤔😵💫
Please
This might be doable...
I ride mine without a rider and it’s handles and jumps better but gets more beat up when running. The rider is kind of the cushion for flips
@@dogdiablo18ryan92
👍🏻 Modify time. Thanks
Have u ever had a bike wheel spun it and tryed to turn it ?
(Fly wheel enuertiour) parden my spelling,
Avc and bit of air tech
Avc . Lean knob 100+ raise the roller peggs ,0 lower them , fly wheels
Wont work in water.. no fly wheel no balance..
5:57 e pe
The flywheel is on on all the actual bench testing a bit later in the video.
I to want to no how to make it perform, and look like it's really being ridin.
the secret is not to buy until the version 2, maybe 3.
said the broke guy 😅
Or buy the 1st,2nd and 3rd
Saw a guy that cut down I guess a smaller truck tire and it actually looks pretty good...S P A R E T I R E S right!!
I saw that too! Ill do it if I have to but for now I just will try to minimize tire damage as I hunt for a new rear.
They were proline badlands 2.2
Bro, can you make a video about how to switch between the different modes Street dirt and wheelie there’s no clear video out there for that
Im not sure if I can make a whole video on just that since those are very straightforward but Ill see what I can do!
you need slo-mo
Im going to attempt to get slow mo for this. I have some ideas as to how I might be able to see the motor slow down.