Does gyro location matter?

[Dan B.]

When I was a noob, I pulled the electronics including the Reedy gyro receiver and swapped it into another truck. The orientation of the installation was different (swapped in 180°?) and it caused the gyro to work “backwards.” It took me almost a full pack to figure out why the truck was totally undriveable. I either had to flip it, or reverse it with the radio, I don’t remember which.

 

[SrC]

Does a gyro behave differently based on location?

Front, middle, rear, etc.

I don'think so at all.
It makes sense to "think" that the a Gyro should be at perfect dead center on the chassis and Flat but the way these are designed, It can be located anywhere as long as it is firmly rigid to the chassis and either mounted flat or on its edge. Once mounted properly per the instructions, only then should it be calibrated.

When I was a noob, I pulled the electronics including the Reedy gyro receiver and swapped it into another truck. The orientation of the installation was different (swapped in 180°?) and it caused the gyro to work “backwards.” It took me almost a full pack to figure out why the truck was totally undriveable. I either had to flip it, or reverse it with the radio, I don’t remember which.

Most quality Gyros have a "Reverse" setting for that reason. Others calibrate the direction on their own.
Reedy Gyro Receivers must suck.. Anything Reedy does. All their RTR stuff .... TA Radios ALL suck, big time. Been there.
Except their Reedy $High end$ Race ESC's and Motors, if anything.
I only use "Standalone" Flysky Gyros now. The GC-401's. Which have 3 pre-settable Curve rates, depending on how you will drive the rig. Whether for Bashing, Track use or Speed running.
Futabas' are the best Standalone gyros out there, hands down. But at $100.00 not for me.
SkyRC GC-401 and even the GC-301 work perfectly. And at 1/3 the price of a Futaba.

 

[jkflow]

We are mixing technologies, and I also made a silly mistake because of it.
All a gyro can do is detect rate of change, nothing else, rest is calculated based on this value.

There is a 'gyro', all it can detect is 'rate of change', doesn't matter how you mount it, but obviously you want to mount it where rate of change is the greatest. This is a 2D version.

There is a 'gyro' but 3D capable, basically 2 gyros mounted 90 degrees on different axis. (planes)

Last but not least there is a 'gyro' but has added accelerometers, actually called an IMU (DJI etc), accels will give you speed etc.

So, not all gyros are equal, all the responses are based on specific models and gain is gyro specific.
Mounting location of a pure gyro doesn't matter as long as it is on the right plane.

If you experienced a 'reverse' behavior, it has accels as well. They should have a directional arrow on the case.

 

[Dan B.]

If you experienced a 'reverse' behavior, it has accels as well. They should have a directional arrow on the case.

That could very well be the case. I’ll look the next time I‘m into that rig. I was definitely scratching my head for a few minutes, though!

 

[Moonstonemike]

Ok, so I was taking a look at my dumbo gyro and realized sometime interesting about gyro position. I'm going to post a video shortly because it's easier for me to show then to explain.

Me no talk so good like smart people here like @SrC and @Diem Turner

And there should be a way to reverse your gyro if it's correcting in the wrong direction

 

[Moonstonemike]

Sorry for the delay. Everything that could mess up did.

Let the flaming begin ...

 

[Diem Turner]

Don't doubt yourself yet. I still think it's possible different gyro may react different.

lol...it's all good. I don't doubt myself. But I've said before that I'll be the first to admit when I'm wrong and the demonstration of two gyros, one at the axis of rotation and the other 14" away, showing both providing the same level of correction was sufficient for me. But no worries, no harm done. I'll still be as opinionated as I was yesterday.

I don'think so at all.
It makes sense to "think" that the a Gyro should be at perfect dead center on the chassis and Flat but the way these are designed, It can be located anywhere as long as it is firmly rigid to the chassis and either mounted flat or on its edge. Once mounted properly per the instructions, only then should it be calibrated.


Most quality Gyros have a "Reverse" setting for that reason. Others calibrate the direction on their own.
Reedy Gyro Receivers must suck.. Anything Reedy does. All their RTR stuff .... TA Radios ALL suck, big time. Been there.
Except their Reedy $High end$ Race ESC's and Motors, if anything.
I only use "Standalone" Flysky Gyros now. The GC-401's. Which have 3 pre-settable Curve rates, depending on how you will drive the rig. Whether for Bashing, Track use or Speed running.
Futabas' are the best Standalone gyros out there, hands down. But at $100.00 not for me.
SkyRC GC-401 and even the GC-301 work perfectly. And at 1/3 the price of a Futaba.

Depending on your suspension, how hard it's set up and how high the gain on the gyro is set, mounting it rigid to the chassis can create problems as vibrations will cause the gyro to react to bumps in the road. That's why they generally recommend that it be mounted with thick, shock absorbing tape. If this, however, still counts as rigid mounting to the chassis, then I will have said nothing.

I tried the GC-401 and I couldn't get it to work with my Futaba gear. I'm sure it was (more than likely) user error and, on top of that, I can get impatient at times and this was one of those cases where after a half hour I just didn't feel like dealing with it anymore, ordered a Futaba GYC-441 and moved on. The Futaba gyro intuitively worked right away. Yes, $80 is still twice what the SkyRC cost but that was one of those purchases where the cost was relativized by both time savings and performance. It does exactly what it says on the tin with no fuss and that's really all I can ask for.

 

[Dan B.]

Sorry for the delay. Everything that could mess up did.

Let the flaming begin ...

Great visuals, and very interesting to see. Hard to argue with, for sure. But a lot to unpack when you start thinking about mounting points. In all cases, the rotational axis remained in the center of the chassis. I don’t have a single rig that has the receiver/gyro mounted on a center brace. They are all on one side or the other on the deck. Would it make a difference? The arcs would at that point not be equal, but I suspect that in the real world, unless you were the Juan Manuel Fangio or Ayrton Senna of RC driving, then the effect would be pretty negligible. And could probably be tuned in very well with a decent radio. Thanks for a great video!

lol...it's all good. I don't doubt myself. But I've said before that I'll be the first to admit when I'm wrong and the demonstration of two gyros, one at the axis of rotation and the other 14" away, showing both providing the same level of correction was sufficient for me. But no worries, no harm done. I'll still be as opinionated as I was yesterday.

Depending on your suspension, how hard it's set up and how high the gain on the gyro is set, mounting it rigid to the chassis can create problems as vibrations will cause the gyro to react to bumps in the road. That's why they generally recommend that it be mounted with thick, shock absorbing tape. If this, however, still counts as rigid mounting to the chassis, then I will have said nothing.

I tried the GC-401 and I couldn't get it to work with my Futaba gear. I'm sure it was (more than likely) user error and, on top of that, I can get impatient at times and this was one of those cases where after a half hour I just didn't feel like dealing with it anymore, ordered a Futaba GYC-441 and moved on. The Futaba gyro intuitively worked right away. Yes, $80 is still twice what the SkyRC cost but that was one of those purchases where the cost was relativized by both time savings and performance. It does exactly what it says on the tin with no fuss and that's really all I can ask for.

I’ll be playing more and more with gyros this year. I do try to resist jumping on bandwagons, but from everything I’ve heard from pretty much everyone, I’ll most likely be getting a Futaba gyro. And I’ll be tuning it in with my budget RadioLink R6!
Kind of like Colin Chapman setting up a chassis for Mr. Bean...

 

[Diem Turner]

Great visuals, and very interesting to see. Hard to argue with, for sure. But a lot to unpack when you start thinking about mounting points. In all cases, the rotational axis remained in the center of the chassis. I don’t have a single rig that has the receiver/gyro mounted on a center brace. They are all on one side or the other on the deck. Would it make a difference? The arcs would at that point not be equal, but I suspect that in the real world, unless you were the Juan Manuel Fangio or Ayrton Senna of RC driving, then the effect would be pretty negligible. And could probably be tuned in very well with a decent radio. Thanks for a great video!

I’ll be playing more and more with gyros this year. I do try to resist jumping on bandwagons, but from everything I’ve heard from pretty much everyone, I’ll most likely be getting a Futaba gyro. And I’ll be tuning it in with my budget RadioLink R6!
Kind of like Colin Chapman setting up a chassis for Mr. Bean...

I'm really happy with my Futaba unit and can't think of a reason to dissuade anyone from getting one. To my mind, $80-100 isn't an unreasonable amount of money and, from my experience, not all gyros are created equal. I didn't like how the integrated gyro in Radiolink and Flysky felt, whereas the Futaba performed how I had imagined a gyro should feel right from the jump. But, as always, that was just my experience. YMMV.

 

[Dan B.]

To my mind, $80-100 isn't an unreasonable amount of money

Well, it’s a hell of a lot cheaper than the XLX2 and the custom wound 5670 TP you made me buy, dammit.

 

[Diem Turner]

Well, it’s a hell of a lot cheaper than the XLX2 and the custom wound 5670 TP you made me buy, dammit.

You didn't say thank you.

 

[SrC]

lol...it's all good. I don't doubt myself. But I've said before that I'll be the first to admit when I'm wrong and the demonstration of two gyros, one at the axis of rotation and the other 14" away, showing both providing the same level of correction was sufficient for me. But no worries, no harm done. I'll still be as opinionated as I was yesterday.

Depending on your suspension, how hard it's set up and how high the gain on the gyro is set, mounting it rigid to the chassis can create problems as vibrations will cause the gyro to react to bumps in the road. That's why they generally recommend that it be mounted with thick, shock absorbing tape. If this, however, still counts as rigid mounting to the chassis, then I will have said nothing.

I tried the GC-401 and I couldn't get it to work with my Futaba gear. I'm sure it was (more than likely) user error and, on top of that, I can get impatient at times and this was one of those cases where after a half hour I just didn't feel like dealing with it anymore, ordered a Futaba GYC-441 and moved on. The Futaba gyro intuitively worked right away. Yes, $80 is still twice what the SkyRC cost but that was one of those purchases where the cost was relativized by both time savings and performance. It does exactly what it says on the tin with no fuss and that's really all I can ask for.

Sometimes a specific Servo will merely cause Gyro issues with some brands.
I find it odd that some Surface Gyros specify completely different ways or types of servo tape to use. They all use the same type of Sensor. So it should not even really matter.
But I guarrantee that if you were to use basic velcro to mount the Gyro, it would give you problems. Usually Oscillation issues.

>>There will always be "Vibration" with any Surface RC chassis. No way to truly isolate a Gyro from it. Gyro Mfrs understand this already.
It is not chassis "Vibration" to worry about. More about if the Gyro tends to "Shift" in place, even the slightest, that will cause oscillation and other Gyro issues. Because the Gyro will shift off it's Axis. Like when some guys use Velcro for mounting. This causes an imprecise Yaw rate response by the Gyro to the servo. Taxing the servo needlessly and gets them hot running.
So firmly mounting a gyro is key. Just follow the specific Gyro brands Instructions for mounting. They even sell Gyro specific $mounting tape$. Forgot who makes it.
I think that's just snake oil.
Having to use a "Special Tape" for a Gyro, Probably means the Standalone Gyro or Rx Gyro is probably crap to begin with. And the Mfr. thinks a Certain tape or way will be better??? Not.
I use 3M automotive Tape. I may double layer it, just to prevent Hard Shocks from impacts causing a broken Gyro PCB, i.e Chassis slap.
.

 

[jkflow]

Special tape will eliminate those micro-vibrations, if you have ever seen old drone footage from the earlier days you could see the 'jelly' video due to those vibrations. Keep in mind that gyro will report changes in angular rotation and a constant back/forth, even if minor, will impact performance.
Again, there is a gain (software) and filter (Software and hardware) function built into the overall design. Just because they use the same sensor part doesn't mean that external electronics are not different. Truly no idea myself on all the differences on the gyros out there, this is just reality based on experience.
Filters will make the gyro 'less sensitive' while no filter will be immediate and highly responsive but that results in 'jitter' or spikes in responses.

So yes, I can see that different (manufacturers) gyros behave differently, of course this is assuming that they truly have standalone designs and not use an OEM core and only change the housing/labels like they do on Lipos or other stuff.

 

[LipoShirly]

Very interesting thread, just when I thought I knew what I was doing......

Mounting location of a pure gyro doesn't matter as long as it is on the right plane.

My initial logic told me this was wrong, but did some googling and finally had my Ah-ha moment, @jkflow has got it spot on.
Most important thing to remember about a gyro is that it only measures rotational forces about its own axis (see below)

A gyro does not respond to linear forces, such as moving side to side, and for that example go back to @Moonstonemike 2nd video, when he does linear move of side to side , the gyro doesn't respond.

Now go back to the @Moonstonemike 1st video with straws ( excellent example by the way ). With the 2 gyros mounted to the same moving stick, you can see that as the stick pivots from its end point, the measured rotation of each gyro is exactly the same at all times. Example, move the stick 90 degrees , each gyro is now 90 degrees away from its original direction, and they arrived there at exactly the same time, and the outputs of each along the way would be identical along the entire arc. Now, and here's where I was confused, the linear speed of the gyros are completely different. The outer unit had to travel much faster on that outer arc to arrive at the same time, but (Ah-ha) the gyro does not respond to linear forces like an accelerometer.. those forces are ignored.

Most instructions that I've found (which is few, you must have to buy product to see manual) actually say it doesn't matter where you put it, or how its oriented in regards to the vehicles direction, but most recommend middle of the vehicle to limit the vibration.

@jkflow mentions gyros with accelerometers on board, those are a completely different beast with applications more in the drone or flight world, or with vehicles where actual position information is needed. Every RC steering assist that I could find was gyro only.

So, not all gyros are equal, all the responses are based on specific models and gain is gyro specific.

Very true..... the actually gyro IC is comparable or equal.... but the end products can be very different based on how the control loop is tuned. The dumbos give you a (proportional) gain control and that's it , the more expensive units give you other values to tune, essentially getting into the I and D of the PID loop.

So, long answer, (see above)
short answer, it doesn't matter where you put it or what orientation you put it in, just mount it securely where vibrations are a minimum.

 

[SrC]

We are mixing technologies, and I also made a silly mistake because of it.
All a gyro can do is detect rate of change, nothing else, rest is calculated based on this value.

There is a 'gyro', all it can detect is 'rate of change', doesn't matter how you mount it, but obviously you want to mount it where rate of change is the greatest. This is a 2D version.

There is a 'gyro' but 3D capable, basically 2 gyros mounted 90 degrees on different axis. (planes)

Last but not least there is a 'gyro' but has added accelerometers, actually called an IMU (DJI etc), accels will give you speed etc.

So, not all gyros are equal, all the responses are based on specific models and gain is gyro specific.
Mounting location of a pure gyro doesn't matter as long as it is on the right plane.

If you experienced a 'reverse' behavior, it has accels as well. They should have a directional arrow on the case.

I find that Surface Gyros operate in X and Y planes/ axis, 2 dimensions. Air RC Gyros are different, yeah with Accelerometers. and in 3 planes of direction.

 

[parcou]

This is a great read and over my head. I favor gyro or AVC by Spektrum but not sure its correct placement. Without the software tuning from the DX5C I would hate it. Even with that the settings all different from each off road rig plus surface bashing it on tires make a difference in the calibration...take a lot of time to dial it right. Happy in my case I'm not just turning a dial or knob left to right as my only options.

Good talk... learning a lot.

 

[SrC]

Traditional surface RC Gyros (standalone or Rx integrated) control only the Steering servo. And have a St. Gain setting. Some also have "Presetable" curves for different driving scenarios. Like the SkyRC GC-401.
Spektrum AVC Rx's apparently have Both ST and Throttle control. Throttle AVC gave me significant issues when Speed Running, FWIW. (throttle cutting when I don't want it)
The Spektrum RTR Radio AVC setups only have Steering Gain adjustments (a single knob for "ST Gain" on the Radio)
When Spek. AVC is binded to a Spektrum Upgrade radio, i.e. DX5C, Rugged or Pro, there is a separate Gain setting for Both ST and Throttle. Along with a single Priority Setting which dials in More or Less Autonomous control over Both ST and Thr. Gain. I put my Priority close to 100%. So my manual radio input remains mostly in control.

Throttle AVC is Not good for Big Air bashing or Speed running or on a Technical Track.
Not that any type of Gyro is even allowed for Club level Competion. It is not.
Just my observations.