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RC helicopter gyro as drift control system on E Firestorm

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RC helicopter gyro as drift control system on E Firestorm

Old 01-20-2009, 02:26 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

Would it be possible to use the gyro as a corrective roll sensor by shifting it 90 degrees? Ie. so when the truck starts to flip, the steering corrects and hopefully keeps it on the ground? Or is it not really designed to work that way...
Old 01-20-2009, 02:43 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

Yeah, I can't think of a reason why that wouldn't work. Just change the axis of the gyro.
Old 01-20-2009, 03:27 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm


Wait, what do you mean "start to filp"?!

I use it for the counter steering..

It basically counter steers for you when it sense too much rotation.. (keep it going straight if you will)




ORIGINAL: Access

Would it be possible to use the gyro as a corrective roll sensor by shifting it 90 degrees? Ie. so when the truck starts to flip, the steering corrects and hopefully keeps it on the ground? Or is it not really designed to work that way...
Old 01-20-2009, 03:49 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

He's talking about turning the gyro so it detects when one side of the car starts to come off the ground. The car would then steer into the turn to stop the lifting.
Old 01-20-2009, 04:05 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

That would be kind of interesing...
Old 01-20-2009, 04:29 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

Been thinking of trying the gyro bit for a while. I also fly helis, and my poor Trex is down for... ehm... extensive... well it's not gonna fly again for a little. I've used a few different gyros in helis, and those same gyros in planes. It was tricky to set up for the planes, but the effects were interesting. I've noted considerable 'drift' with many entry-level gyros, the stock Blade 400 gyro being one of them. Don't get me wrong, it's not a LOT of drift (5 degrees/second max) and as far as drifting goes doesn't really matter. However the drift varies a lot, and it lacks a certain kind of authority. Straight lines would be rather difficult. There's nothing like a 'good' gyro like a Futaba GY401, though. My heli went from having a 'whimsical' do-what-it-wants feel to rock solid when I used the GY401.

Has anyone looked into any of the 3-axis "Autopilot" controllers?

It may not be race legal at all, but the concept of an "intelligent" vehicle is very cool indeed...
Old 01-20-2009, 04:57 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

Head holding doesn't seem to work as well as rate mode on a car, so drift is not an issue. In rate mode you can just adjust the tracking with the subtrim and it'll drive straight.

I don't think cars require anywhere near as much precision as helicopters. I am using the cheapest of the cheap gyros right now and it works fine.

I don't think I'd put a GY410 on a car. The hard knocks and vibration would probably kill the SMM module.
Old 01-20-2009, 05:26 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

ORIGINAL: eaterofdog
He's talking about turning the gyro so it detects when one side of the car starts to come off the ground. The car would then steer into the turn to stop the lifting.
Exactly, or maybe even couple two gyros together to combine the idea, so you get both yaw and roll stabilization, with a lot higher gain on the roll-sensing gyro. It's just that when you start talking about putting gyros on MTs, it's not quite the same as putting it on a drifter.
Old 01-20-2009, 05:33 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

Oh one is going on my revo for sure. I may try it on a micro-t that has an aftermarket rx as well. I could see the brushless micro/mini crowd using them with how over powered the motors are relative to the size of the car/truck.
Old 01-22-2009, 12:52 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

I just put one of those cheap Esky gyro's on my savage and i have a question.....I have to set the gain on the gyro and this arvo i was doing a few high speed runs in my street and I set the gain as best as i could....if i put any more gain the front wheels start wobbling at higher speeds, the question is would i need to raise or lower the gain when i switch to a surface with less traction like grass or dirt???

For those of you wondering whether you can put a gyro on your throttle servo....it wont work, if you go full throttle and the car doesnt go straight up the gyro would freak out because it would be like turning full lock but the car keeps going straight (if a gyro is connected to steering servo).....it just wont work.
As far as an anit-roll over gyro, i dont think that would work either because of the same principle.......when you turn and the car doesnt flip over the gyro would freak out like described above.

Someone also said that the gyro would stop powerslides.......wrong, it greatly decreases the difficulty of drifting, it does all the counter-steering for you with MUCH more precision than any human. HPI called it a "Drift box"......the "D-box" is just a rebranded Futaba G190.....and i agree that $90 is a lot of money for a rate gyro. Apparently HH gyros dont work as well as rate gyro's.
And the cheap gyro's should work just fine because they are programmed to work on a heli which is much more precise than a nitro car. So a "bad/cheap" gyro for heli's should be good for cars.
Old 01-22-2009, 06:40 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

The wobbling is the car version of "wagging," so the gain needs to go down. Gain would be higher on dirt than pavement, because the tires grip and react quicker.
Old 01-22-2009, 07:29 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

now when you say "Gain would be higher on dirt than pavement, because the tires grip and react quicker" are you saying it grips and reacts quicker on pavement??
The way you worded it is a bit confusing.
but are you sure the gain should be increased as traction decreases? because i have heard otherwise on different forums and i dont want to call who's wrong and who's right just yet. Although increasing the gain on slippery surfaces makes more sense to me than decreasing it.

Thanks, Daniel
Old 01-22-2009, 08:42 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

I should say if the tires grip and react quicker on pavement. Analogous to installing larger tail blades on a heli. Yes, you want the gain to go up as traction goes down. Probably not a whole lot though.
Old 01-22-2009, 09:09 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm


ORIGINAL: legine
For those of you wondering whether you can put a gyro on your throttle servo....it wont work, if you go full throttle and the car doesnt go straight up the gyro would freak out because it would be like turning full lock but the car keeps going straight (if a gyro is connected to steering servo).....it just wont work.
As far as an anit-roll over gyro, i dont think that would work either because of the same principle.......when you turn and the car doesnt flip over the gyro would freak out like described above.
True, true, since the gyro is not seeing the rotation on axis it expects, it would try to make it happen.

I agree the throttle thing would not work that well, but I bet you could set it up to do wheelies on certain vehicles. When the throttle increases, the gyro would expect the front end of the car to lift (rotate on it's axis) and if it didn't the gyro would apply throttle to lift the front. If the front begins to lift to high, the gyro reduces throttle to keep it down. On a vehicle that wheelies easy, you could try to tune the gyro to balance on the back tires. The vehicle would be completely useless otherwise. Somebody has to try this.

The anti-roll over thing would probably try to balance your vehicle on two side wheels. You make the turn and the gyro expects the side of the vehicle to lift, and would adjust the steering to try to make that happen. Maybe instant donuts anytime you try to turn?
Old 01-22-2009, 09:36 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

I'm running a G190 in my speed buggy, lots and lots of 'saves' from bumps and jumps at speed (I just use any old street or alley), very useful device if you are wanting speed with not a lot of breakage from hitting things. I found that having your wheels balanced and suspension on the softer side helps a lot with occillation, although it can still start up above 50-60 mph if the car is 'hit' right. Turning the gain down decreases this effect, but then it seems to not correct as well to keep the buggy in a straight line. On this winter reconfiguration I'm doing, I noticed on the bench that using a double layer of the foam tape seems to help keeping the occillation effect down compared to a single layer. I cant wait for the snow to go away to see how this works on the street. I think the key is keep the vibration of the vehicle down as much as possible for best results.

Having a fast servo is a plus as well with these.
Old 01-22-2009, 09:54 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm


ORIGINAL: SidewaysLS4
and suspension on the softer side helps a lot with occillation, although it can still start up above 50-60 mph if the car is 'hit' right.
Ahh if the front wheels come off the ground for a second the gyro may over correct because the car is not responding to the counter steer. Sounds like wheelies could cause a problem as well.

I bet high speed wobbles are caused by slop in the steering.

Good point about the servo, I have a new Spektrum race servo I should try.
Old 01-22-2009, 10:02 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm


ORIGINAL: eaterofdog


I bet high speed wobbles are caused by slop in the steering.

Good point about the servo, I have a new Spektrum race servo I should try.
The steering is nice and precision-style on my buggy. I think that it is just too much gain on the gyro to give the desired effect of enough countersteer to keep it straight when the car is deflected, along with the servo being not fast enough...although it is a .11 second servo. I'm wondering if a faster servo would help, but I dont want to spend over $100 for a servo that fast with enough torque, so maybe my double foam tape idea might help, we'll see in a few months. Or just keep it on a smoother road and under 60mph, lol.
Old 01-22-2009, 10:09 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

From my playing around with a gyro, I don't think the gyro 'expects' anything. All it does is the basic stabilization effect. When it sees a sufficient change in the rotational velocity, it moves the servo a little bit the other way. How much it moves the servo depends on the gain.

I can hold the wheel to the right and it still turns right, just based on the additive effect (the gyro is adding the stabilization factor to my steering, not preempting it). The stabilization factor it adds is much smaller than my overall steering range. I tried it on a crawler and when I rolled the crawler's body to the right very quickly, the wheels would counter-steer left a bit, but then crawler can't be made to tip over normally; still it seems like the concept could work in theory, worth trying at least.

Anyways, trial and error or experimentation is better than pure speculation, just try it for a while and see if you can make it work... if it works make a video to show the others.
Old 01-22-2009, 10:44 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

Anyone try doing some channel mixing linking the 3rd channel to the steering on the radio, with a remote gain gyro of some sort getting the gain info from the 3rd channel? I'm wondering if something like this could help getting consistant full steering lock at slower speeds, without having to deal with what the gyro thinks the maximum rotation should be. My epa's are maxed out already, it helps, but I want the wheels to be at full lock when I steer full lock and keep the gyro gain level where it is now.
Old 01-22-2009, 10:52 AM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

Mixing the gain with another channel? Cool idea. Maybe mix the gain with the throttle? Higher throttle = more gain? The gyro just interferes at lower speeds, as you were saying.
Old 01-22-2009, 12:45 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

It sounds to me like you want less gain at higher speeds so the gyro will make smaller corrections.
Old 01-22-2009, 12:57 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

I set up my Slash with an E-flite gryo, more or less the same as the one used on the Blade 400. I then ran the truck in two different settings: backyard short track, and open desert. The centerpoint drift issue still shows through with the gyro, in the sense that it needs to be re-trimmed every 5 minutes or so. Not sure if it's a temp thing or a voltage thing. Here's the good and bad:

+4wd-esque handling at most speeds on low to medium grip surfaces (high gain).
-I ran into the high-speed wobble others reported. High gain, steering slop, tire roll, and chassis roll seem to be the contributing factors. Possibly steep kickup too.
+On the tight course and with reduced gain, stability under braking and hard out of corners was astounding.
+Fishtailing? What's that?
-You can go ahead and forget about being able to drive straight in reverse.
-Somewhat finnicky to maneuver at LOW speed.
+The truck held straight on off-camber straightaways.
-Excessively sensitive at certain speeds. This can be fixed with more adjustability, and I don't have much to adjust on the TRX radio.

To anyone considering trying this out, I say give it a go, as long as you can easily disable or bypass the gyro. It worked wonders in certain conditions, but on tight, technical courses it can have you tripping over your own feet.

eaterofdog: Good point on the GY401 bit. But I still think I'm going to try it - the setup I tried lacks the authority I know the 401 has. Durability-wise, the 401 would get its own box, to keep dirt out, and some degree of vib. damping. I've seen these gyros survive some hairy heli crashes, which are inherently very violent. A clean, sealed box riding on a flexy chassis with good suspension should be a vacation for it
Old 01-22-2009, 01:12 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

ORIGINAL: d31805
eaterofdog: Good point on the GY401 bit. But I still think I'm going to try it - the setup I tried lacks the authority I know the 401 has. Durability-wise, the 401 would get its own box, to keep dirt out, and some degree of vib. damping. I've seen these gyros survive some hairy heli crashes, which are inherently very violent. A clean, sealed box riding on a flexy chassis with good suspension should be a vacation for it
I'm very interested to see how the delay adjustment on the 401 will help. The delay is pretty much required on a helicopter to get a dialed in tail. I bet some high speed wagging could be gotten rid of with a little delay.

Your testing seems to confirm Sideway's idea of mixing the throttle and gain.
Old 01-22-2009, 01:44 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

I'm very interested to see how the delay adjustment on the 401 will help. The delay is pretty much required on a helicopter to get a dialed in tail. I bet some high speed wagging could be gotten rid of with a little delay.

Your testing seems to confirm Sideway's idea of mixing the throttle and gain.
The delay setting will help a LOT.

I've been wanting to try this for years but never got motivated - nothing I had was fast enough to need stability enhancement... This is a GREAT concept, and the E-flite gyro does a great job, but it still feels crude. The 401 will push this to the next level.

Kudos to Sideways for the mixing idea - I once used a similar mix in one of my planes to counteract adverse yaw (yaw\roll resulting from prop torque\propwash). At throttle settings > 50%, it would start giving Right aileron input. Although my experience with that tells me that there are many other factors that would need to go in to an automatic/variable gain. For example, the Slash is VERY sensitive to rollover when coasting down from a high speed. The gyro made this much easier, even pulling the truck back down a few times when it was up on 2 wheels. I'm not saying it's not worth while or that I won't try it, just that it'll need some stock market graph curves

I'll most likely try the 401 today or tomorrow. Now I'm really stoked to try it. I'll post my findings.
Old 01-22-2009, 01:52 PM
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Default RE: RC helicopter gyro as drift control system on E Firestorm

Also regarding gyro drift on piezo gyros, try this. Power everything up and let it sit for three minutes, then power cycle before driving. Piezos like to be warmed up and reset. Helis do the same thing unless you warm them up.

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