tilt mechanism of 3-wheeler scooter

[Afzal Ahmad]

Hello folks, I am a Mechanical Engg. student(bachelor). I came across a 3 wheeler scooter on the internet which has a unique swirl/tilt mechanism for the safety and improves the dynamism of the vehicle. later after some looking, I found there were several scooters using this kind of mechanism. But I could find the how these mechanisms really works. I am very curious to know what are fundamentals of these designs and how suspensions are mounted and what is fatigue life.

 

[IRstuff]

you could contact the manufacturer:

TTFN (ta ta for now)
I can do absolutely anything. I'm an expert!

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[GregLocock]

Here's a picture of the guts of the honda gyro's joint, but with no internal details. I'd have thought it would need active control, yet at the same time the forces are quite large which doens't seem compatible with that thing.

http://tiltingvehicles.blogspot.com/2009/08/honda-gyro.html

Cheers

Greg Locock


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[waross]

It may be a simple swivel.
The dynamics of motorcycle cornering are a little counter-intuitive.
Most motor cycles are leaned by the rider shifting his weight slightly.
Depending on the geometry of the bike, the rider may have to apply counter steer to develop enough lean for sharper corners and greater lean angles.
With one of my bikes I experimented by pushing ahead on one side of the handle bars.
If kept my body as stationary as possible and I pushed on the right-hand bar, the bike would make an imperceptible turn to the left, but the turn would cause the to lean to the right and curve to the right.
Due to the fork angle and axle offset, the handle bar would push back against my hand and a balance could be reached for the degree of lean and arc of turn that I wanted.
On a later bike, on a high speed turn on a highway, I actually had to consciously steer the opposite way to increase my angle of lean and reduce my turning radius.
When I first started riding that bike, I almost lost it on a couple of higher speed highway curves bacuase I couldn't develop enough lean with only shifting my body weight.
With a simple pivot that scooter should be able to be cornered by the rider leaning into a curve.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[GregLocock]

Yes, I'm beginning to suspect that might be the case, that is the driver still has to control the thing. Here's the title of a very long paper saying tain't so, but watching youtubes of them racing suggests that the driver doesn't just sit there like a pudding

DETC2018-85087
1 Copyright © 2018 ASME


SIMULATION BASED TRAJECTORY ANALYSIS FOR THE TILT CONTROLLED HIGH
SPEED NARROW TRACK THREE WHEELER VEHICLE

Jigneshsinh Sindha∗
IIT Kharagpur
Kharagpur, India 721302
Email: sindha.jignesh@gmail.com
Basab Chakraborty
IIT Kharagpur
Kharagpur, India 721302
Email: basab@see.iitkgp.ernet.in
Debashish Chakravarty
IIT Kharagpur
Kharagpur, India 721302
Email: dc@mining.iitkgp.ernet.in
ABSTRACT
Small sized three wheeler electric vehicles (EVs) are gaining popularity in many developing countries because of its low
cost operation and excellent manoeuvrability. However, usage
of such a 3Ws usage is limited to low speed application such as
last mile public transport. Vehicles with such configuration are
not well accepted for personal mobility. If the safe speed of such
a vehicles are improved, such a vehicles can also become viable to personal transport. Active tilt control (ATC) systems are
seen as one of the possible solution to improve safe speed of narrow track 3Ws.Literature indicates that many attempts have been
made for establishing active tilt control system on 3W vehicles
for enhancing stability of ATC vehicles and promising results
were obtained. This paper presents simulation based analysis of
the ATC 3W electric vehicle. This work is part of full scale experimental prototype development for the narrow track ATC 3W
vehicle with one wheel in front configuration. The primarily focus of this work is to address vehicle dynamics and trajectory
related issue of the tilting 3Ws.
A multi-body model of ATC 3W vehicle using single track lateral
dynamic model with nonlinear tire characteristics was prepared
in SimMechanics. The lateral dynamic outputs in terms of the
trajectory followed by vehicle were compared for the constant
steering inputs given to non-tilting vehicle, tilting vehicle with
direct tilt control(DTC) system and tilting vehicle with Steering
direct tilt control (SDTC) system. Two critical driving scenarios
of U-turn and Lane change manoeuvre are analyzed. It is observed from the results that there is certain trade-off in selecting
a tilt actuator and controller so as to minimize the jerks in the perceived acceleration due to high gain and minimize the tilt angle
error to ensure proper stability improvement. It is also identified that the controller must be tuned to the predictable trajectory
control, in addition to the main task of reducing the load transfer
across the rear wheel axle. The model presented in the paper is
used to understand the performance of DTC and SDTC control
strategies during potentially dangerous manoeuvres. The desired
path following ability of the vehicle is the main measures considered for the analysis.

Cheers

Greg Locock


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[waross]

I think that those guys are seriously overthinking the issue.
I doubt that any of them has any real motorcycle experience, and did not pay attention when riding their bicycles.


Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!

 

[GregLocock]

Agree 100%. The Honda Gyro system MAY have one mechanical input, you could for example decide to have a jack driven by steering input, but I suspect for such a light vehicle it is more like riding a conventional bike, and it is merely a rotational joint.

Cheers

Greg Locock


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[drawoh]

Afzal Ahmad,

Ask yourself why you would design such a thing. Without that rotating system, the vehicle would be way simpler.

Three-wheeled vehicles flip over because the centre of mass is closer to the outside wheels than it would be on a four-wheeled vehicle. If rotating the driver and front wheel moves that outer wheel line away from the centre of mass, the vehicle would be safer. This affects how you design the rotating action.

Maybe they just want the thing to look crazy, and they drive very carefully.

Don't overestimate the amount of engineering that goes into custom vehicles. A lot of these things are built by mechanics and welders trying to build something cool.

--
JHG

 

[drawoh]

Afzal Ahmad,

Google "thin section bearings". Kaydon specialises in them. These should be strong enough to rotate the front of a vehicle and manage moment loads. I do not know how they would handle impacts. They can be very expensive.

--
JHG

 

[waross]

As the front section and the driver lean into a turn, the center of mass is shifted towards the inside of the turn.
If a rotating bearing works on one of these, I am sure that it may be scaled down for a scooter.

Bill
--------------------
Ohm's law
Not just a good idea;
It's the LAW!