Simple gyro balancing for velomobiles & recumbents

Erm. There are precedents of 'gyrocars', but you'll be losing a ton of energy just to keep the flywheel spinning, and it weights... a LOT! When you scale the model, include the rider and scale the FLYWHEEL as well, you'll see what I mean!

Or you'll have to spin it extremely fast, and it it can become an ordnance of death in case of a crash. If you need singletrack dynamics but want slow/zero speed stability just go with a tilting narrow-track bike like, say, Toyta iRoad.

I've done some research, this is pretty hopeless - maybe in some VERY, very niche application.
 
BMW Self Riding Motorcycle – BMW R 1200 GS
https://youtu.be/XMuMoZlVYqs
 
BalorNG said:
Erm. There are precedents of 'gyrocars', but you'll be losing a ton of energy just to keep the flywheel spinning, and it weights... a LOT! When you scale the model, include the rider and scale the FLYWHEEL as well, you'll see what I mean!

Or you'll have to spin it extremely fast, and it it can become an ordnance of death in case of a crash. If you need singletrack dynamics but want slow/zero speed stability just go with a tilting narrow-track bike like, say, Toyta iRoad.

I've done some research, this is pretty hopeless - maybe in some VERY, very niche application.

Here's a "VERY, very niche application":
A small (~30cc) 2 stroke engine, spinning a generator, doing double duty as a gyro.
ie: The whole engine, with spinning crankshaft, and the generator, spinning a flywheel full of magnets, does does double duty as both a series hybrid (range extender) and a gyro.
:)

Lit Motors is developing a Gyro Bike:
[youtube]gdGjUvWGP-k[/youtube]

Check the: use regen to spin up gyros for a stop; spin up drive motors with gyro momentim when pulling away:
https://youtu.be/yEy__8LXBjs?t=615
ie: The gyros here do double duty as a 'battery' (95% efficient apparently) to store braking momentum for pull away.
Last I checked it was the damn batteries that cost an arm and a leg in E-biking.

A search brings up some interesting results, like an 'in wheel' gyro to teach kids to ride and various university and DIY projects. .
 
Flywheel kinetic energy storage does kind of make sense, but only in case if your battery is way too small to absorb regen current, supercaps can do same duty and otherwise simply adding a bigger battery achieves same goal AND gives more range.

A small range extender/genertor plus gyro IS interesting, but again - the problem is with weight of the vehicle and the weight of the gyro. You cannot have meaningful contribution to balance with a small flywheel, you cannot have it spin extemely fast lest if flies apart like a shrapnel grenade, and must be housed and made to exacting tolerances to prevent vibration - hence, very expencive... or simply very heavy and large, which is a very hard sell!

Unfortunately, Lit motors gyrobike seem to be vaporvare - and this is likely the reason. Yes, it can be done, but a leaning narow-track vehicle like Toyota iRoad achieves this goals much simpler (and still not popular enough, because for now people prefer large, spacious vehicles for personal transportation)

But your idea is pretty interesting in a much narrower scope - adding a gyro to *steered* accembly might add enough additional gyroscopic inertia to conribute to stability and self-stability of a fully faired singletrack vehicle lacking conventional trail because trail is a lever arm for side force (stemming from wind gusts, for instance) to produce steering input, and according to data I've gathered you either need very short trail and have it twitchy at high speed, or have it highly unstable in gusty winds conditions.

I'm currently trying to experiment with that, by simply weighting down the steered wheel, and eliminating convetional trail while retanining return to center force that is important for control with virtual pivot system.

This system can be much, much smaller and lighter than something designed to directly affect vehicle balance, because it should only affect steering (in possibly advantageous ways), THAT would create steering/balance corrections.
 
BalorNG said:
Flywheel kinetic energy storage does kind of make sense, but only in case if your battery is way too small to absorb regen current, supercaps can do same duty and otherwise simply adding a bigger battery achieves same goal AND gives more range.

A small range extender/genertor plus gyro IS interesting, but again - the problem is with weight of the vehicle and the weight of the gyro. You cannot have meaningful contribution to balance with a small flywheel, you cannot have it spin extemely fast lest if flies apart like a shrapnel grenade, and must be housed and made to exacting tolerances to prevent vibration - hence, very expencive... or simply very heavy and large, which is a very hard sell!

Unfortunately, Lit motors gyrobike seem to be vaporvare - and this is likely the reason. Yes, it can be done, but a leaning narow-track vehicle like Toyota iRoad achieves this goals much simpler (and still not popular enough, because for now people prefer large, spacious vehicles for personal transportation)

But your idea is pretty interesting in a much narrower scope - adding a gyro to *steered* accembly might add enough additional gyroscopic inertia to conribute to stability and self-stability of a fully faired singletrack vehicle lacking conventional trail because trail is a lever arm for side force (stemming from wind gusts, for instance) to produce steering input, and according to data I've gathered you either need very short trail and have it twitchy at high speed, or have it highly unstable in gusty winds conditions.

I'm currently trying to experiment with that, by simply weighting down the steered wheel, and eliminating convetional trail while retanining return to center force that is important for control with virtual pivot system.

This system can be much, much smaller and lighter than something designed to directly affect vehicle balance, because it should only affect steering (in possibly advantageous ways), THAT would create steering/balance corrections.

I had a quick look at gyros and the physics is ...interesting, if not intuitive.
More study reqd. Sigh... :)

I would say that if you have weight doing double duty; you're saving weight.
ie: If you're building a 2 wheeled, reclining series hybrid anyway; then digging into gyro physics and, if it works (weight, RPMs, etc), implementing a genset/gyro may be worthwhile.
The video/s look promising.

They do seem to have the ability to absorb and transmit large amounts of energy, basically instantaneously.
I don't as yet know how they compare to the new Ultra/Super Capacitors.

When it comes to aero singletrack velomobiles with long trail; they are basically vertical wings:
When there is a crosswind; lift develops on the opposite side of the vehicle.
The center of lift moves forward as the crosswind angle increases from straight ahead. That's OK until the center of lift moves ahead of the front wheel/s.
The real problem occurs when the side wind angle increases to the point where your vertical wing stalls:
ie:
Lets say there's a side wind at 5deg from the left.
You lean the wind and correct steering etc instinctively, with time to react.
But at a crosswind angle of around 12-15deg your vertical wing suddenly stalls:
That means that the 'lift' (likely ahead of your front wheels = leverage) you were leaning left/steering into suddenly disappears with no time to react!
You end up either turning left, or falling over to your left, into oncoming traffic!

Ways to ameliorate that IMHO:
Your vertical gyro idea is certainly interesting, but some other ideas:

Laminar Flow Aerofoils (NASA) where the thickest part of the wing is far back have their center of lift far back.
In your vertical wing that would mean the center of lift doesn't ever get to be in front of the front wheel/s...

Whale turbucles! :)
Do a search for
Whale tubercles wings fans propellers
Basically what this tubercles can do for a velomobile is make the 'vertical wing' stall much more gradually.
That means you have more time to react/correct...

With a wind from the left; the left side of a, so designed body, will be pushed inward, while the right side is sucked/bulged outward.
One could use this side panel deflection as a steering input to auto correct for wind.
How best to do so would take some experimentation with different length levers, geometry etc, but I think it could be made to work well.

The tail of a well faired velomobile is generally cut off to reduce crosswind instability, increasing drag.
I see no reason why a weathercocking rudder-like tail cant be used.
ie: keep the tail, but make it weathercock like a large loose rudder.
This should decrease both aero drag (front and/or crosswind) and the crosswind instability.

Elliptical gears or sprocket/s in the steering mechanism would mean less wheel angle per steering input around the straight line (used when traveling fast) and more wheel angle per steering input as steering input angle increases to the angles used at slow speeds for U turns etc...
 
Logic11 said:
I had a quick look at gyros and the physics is ...interesting, if not intuitive.
More study reqd. Sigh... :)

Yup... my point exactly.

Logic11 said:
I would say that if you have weight doing double duty; you're saving weight.
ie: If you're building a 2 wheeled, reclining series hybrid anyway; then digging into gyro physics and, if it works (weight, RPMs, etc), implementing a genset/gyro may be worthwhile.
The video/s look promising.

Which video? I took a stab at series hybrid using human power, but while fun this make sense only for something that cannot be setup in a 'parallel hybrid' (like above mentioned leaning trike). Using a very small motor, something akin to model motor with a generator that serves as electric starter and flywheel to boot is something I've also been considering as a system for long distance-travel... a triple hybrid, ehehe. Hybrids with modern, efficient motors actually make considerably more pratical sense than pure plug ins - they already achive the goal of efficiency by ability to use mostly electric motors in traffic and utilise gas motors at peak of efficiency, can use both gas and electric infrastructure so no range anxiety.

Logic11 said:
When it comes to aero singletrack velomobiles with long trail; they are basically vertical wings:
When there is a crosswind; lift develops on the opposite side of the vehicle.
The center of lift moves forward as the crosswind angle increases from straight ahead. That's OK until the center of lift moves ahead of the front wheel/s.
The real problem occurs when the side wind angle increases to the point where your vertical wing stalls:
ie:
Lets say there's a side wind at 5deg from the left.
You lean the wind and correct steering etc instinctively, with time to react.
But at a crosswind angle of around 12-15deg your vertical wing suddenly stalls:
That means that the 'lift' (likely ahead of your front wheels = leverage) you were leaning left/steering into suddenly disappears with no time to react!
You end up either turning left, or falling over to your left, into oncoming traffic!

What is interesting, it seems that CoP does not move much with AoA for symmetric airfoils (which velos/streamliners obviously are):
https://vimeo.com/141637747

Also, things are considerably more complex than simply looking at CoP height from contact patches and calculating 'toppling torque' from there. The bike STILL tries to rotate about it's CoG, despte constraints - due to side force causing pneumatic wheels to develop slip angle and 'self-steering' without any actual steering input whatsoever, for instance.

Technically (though I'm not entirely sure) if you co-locate CoG and CoP on same spot right between the wheels and eliminate direct steering input due to steering geometry (trail), your bike shold behave yourself more or less like a velomobile - with wind gusts pushing you to the side slightly in a uniform fashion, which can ONLY be reduced by decreasing side area, 'lift dumpers' like storm strips and increasing overall system mass.

In fact, you want CP height to be somewhat BELOW CG, so the bike will be 'blown from under you' and automatically assume 'leaning into the wind' position.

That would likely require a balast (like a battery) somewhere *high* up in the fairing.
https://motochassis.com/Articles/Aerodynamics/AERO.htm

If you want to automatically cancel out tendency to be blown sideways, you want CG in front of CP a bit, actually.

So, it makes a lot of sense that the best practical fully faired (more or less) HPV so far was Rotator Coyte - long wheelbase, FWD, very upright rider position, very short nose, tail extending a bit behind rear wheel, so CP and CG are somewhere in the middle of the fairing plus large side holes, that are mostly for ingress/egress but also efficient lift dumpers. Of course, they ruin aero considerably but it is still more than fast enough even on pure human power.

yCjQc5hl.jpg



Logic11 said:
Ways to ameliorate that IMHO:
Your vertical gyro idea is certainly interesting, but some other ideas:

Laminar Flow Aerofoils (NASA) where the thickest part of the wing is far back have their center of lift far back.
In your vertical wing that would mean the center of lift doesn't ever get to be in front of the front wheel/s...

Whale turbucles! :)
Do a search for
Whale tubercles wings fans propellers
Basically what this tubercles can do for a velomobile is make the 'vertical wing' stall much more gradually.
That means you have more time to react/correct...

Yea, abrupt stall is bad. Combined with 'laminar foil' design turbulators will considerably increase drag however, but it might be a sacrifice worth making (making them removeable for calm weather seems like a good idea)

Logic11 said:
With a wind from the left; the left side of a, so designed body, will be pushed inward, while the right side is sucked/bulged outward.
One could use this side panel deflection as a steering input to auto correct for wind.
How best to do so would take some experimentation with different length levers, geometry etc, but I think it could be made to work well.

The tail of a well faired velomobile is generally cut off to reduce crosswind instability, increasing drag.
I see no reason why a weathercocking rudder-like tail cant be used.
ie: keep the tail, but make it weathercock like a large loose rudder.
This should decrease both aero drag (front and/or crosswind) and the crosswind instability.

Actually, I suspect that too short a tail actually creates instability on velomobiles.
Rudder-tail is something quite interesting, but actually turned into a full-scale control surface! Since aerodynamics forces are cause of instability, we should be figting fire with fire if you ask me! But that's quite a complex project...

Logic11 said:
Elliptical gears or sprocket/s in the steering mechanism would mean less wheel angle per steering input around the straight line (used when traveling fast) and more wheel angle per steering input as steering input angle increases to the angles used at slow speeds for U turns etc...

Yea, I've though about that. Drastically slowed down steering might be a very good idea for high speed stability, but 'nonlinearity' does not sound too good for singletrack.
I've had idea (since I have to use remote steering anyway) to have two cockpits - one for slow speed steering, other for high speed.
 
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