A Safe Tilting System [Archive]

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Derwin

07-09-2009, 09:16 PM

Below is some information from a guy who has some opinions on the popular tilting systems out there now....

"CLEVER IS UNSAFE tilting vehicle" Says BMW...

Overview of tilting vehicle systems.

" comparisons are restricted because no narrow
simple steer vehicle is yet proved to work other
than the FTC system ..."

" The definition of "narrow" is generally accepted to mean less than a meter , with a FTC system this is easy to achieve. There is every reason to seek a narrow profile... that's the most important
dimension for an urban commuter. However we have included a "wide vehicle".. the CARVER, because its the only vehicle comparable with our system" The Carver although 1.3 meters wide can be outperformed with a FTC system of 1 meters width.

The CARVER is an impressive vehicle. It has received much acclaim. On the down side is a common complaint that the vehicle is too wide. . It has proved that tilting can be enjoyed by anyone, because it recognizes the importance of simple steer as a requirement for a production vehicle. Its use as a commuter does not appear to be their focus.

The "CLEVERr" is a joint venture that has a budget over the 1.5 million
pound mark. Much research has been done evidently, and they recognize
the importance of simple steer control and it is proposed to be a meter
wide, but as yet no working prototype has been produced.

NEWS! the Clever has been revealed and driven by some people who are technically critical of its performance. The result is exactly as I have
predicted for many years as the millions of Euros were being wasted. There is however no doubt about the level of general engineering in the vehicle ... it is superb..... the control system is the problem... see below for updated comments...

The "Naro"... again, there seems to be some confusion as to just how they
will achieve the control..... Proposed to be narrow . No working prototype

Update! There IS a working NARO prototype. TvA fully understands the
principles of this control system. We believe its very unlikely to work
properly. The technical reasons for this are beyond the scope of our website to explain.

I invite anyone to observe the Clever in its videos. [ the NARROW has no video released] The vehicle clearly can't change direction quickly and as such would be dangerous in a normal road environment. Compare the CLEVER with the CARVER videos or with the videos of my vehicle which are available on this site. The CLEVER is flawed because it steers onto its curved path before it tilts... and as anyone
technically minded will explain... this creates centrifugal force initially in the wrong tilt direction which then has to be overcome with hydraulic tilt in the required direction.
The result is a very slow tilt speed capacity.... and if you cant tilt fast you cant change direction fast without overturning the vehicle.

It is a shame that the hopes of many are riding on this vehicle because with its present control system it can never deliver on its great promises.

Unfortunately this wont be the first time that a lot of money has been lavished on a futile control concept.The Mercedes "Life jet" used a similar approach. It was binned for the same reason.

People who trust that the best is being done to achieve a better and more efficient vehicle will remain hopeful... and at least the Clever has brought awareness of the potentials to a wide audience.

I have made many representations to the CLEVER group inviting them to compare their vehicle with mine in a direct comparison to judge the differences for themselves... but have received no acknowledgment of any correspondence.

NOTE: Quoting selectively.

BMW to me: "You are right"....."the [clever] control system..... would never work in real life"...." it is not fail
safe and not operational safe"

BMW then go one to state that they will use the Carvers system. To me: " Our contacts with [Vandenbrink Carver] are very old and very good"...." we know that a running tilting system is already existing and available for us" end of quotes.

I include these insights into the "corporate mind" for the benefit of those who did not [understandably] accept my clear statements [over some years] that the Clever control system "could not possibly work". For some people the integrity of engineering principles... obviously comes last.

All is "presentation"... all is "spin doctored"

http://flytheroadclub.com/forums/attachment.php?attachmentid=892&stc=1&d=1247188582

I maintain that the "Brinks Carver "system is fundamentally flawed for a meter wide vehicle.

As a side note, I should say that the gentlemen who wrote the above comments has developed a system of his own for tilting vehicles.

Derwin

07-09-2009, 09:22 PM

More information from this man...

<meta http-equiv="Content-Type" content="text/html; charset=utf-8"><meta name="ProgId" content="Word.Document"><meta name="Generator" content="Microsoft Word 12"><meta name="Originator" content="Microsoft Word 12"><link rel="File-List" href="file:///C:%5CUsers%5CDerwin%5CAppData%5CLocal%5CTemp%5Cmso htmlclip1%5C01%5Cclip_filelist.xml"><link rel="themeData" href="file:///C:%5CUsers%5CDerwin%5CAppData%5CLocal%5CTemp%5Cmso htmlclip1%5C01%5Cclip_themedata.thmx"><link rel="colorSchemeMapping" href="file:///C:%5CUsers%5CDerwin%5CAppData%5CLocal%5CTemp%5Cmso htmlclip1%5C01%5Cclip_colorschememapping.xml"><style>  </style> [I] [I]<o:p></o:p>

[I]Technical...? [not really.....]<o:p></o:p>
<o:p> </o:p>
Just quickly...... The most important point when you go to "driver induced force tilt" a vehicle mass is the steer angle position of the front wheel/s at any given moment as the tilt action is occuring...[assume front wheel steer]..<o:p></o:p>
..........any steer angle produces a curved steered path ....... ANY curved steered path will produce centrifugal force tending to tilt the vehicle mass in the wrong direction ... [like a car]...... SO..... you don't want to steer before you tilt...... You don't even want to steer AS you tilt, because , if the steer angle gets "in front" of the tilt angle for any given speed, it will restrain the tilt, or even prevent it.. , or worse ,overcome any positive driver applied tilt and send the mass in the wrong tilt direction...or, just as bad if the steer lags too much and sends the mass too far in the right direction!!!... <o:p></o:p>
<o:p> </o:p>
"For any given tilt angle as the tilt is occuring....and speed ,there will be a neutral steer angle which will not be tending to apply more or less tilt." This means that at any given moment the centrifugal force is being balanced by the gravity force acting on the inclined mass.<o:p></o:p>
<o:p> </o:p>
This neutral point must exist at ANY GIVEN INSTANT DURING THE TILT ACTION during any manouver or speed .. IT MUST DO THIS.... or the vehicle will be a pig.<o:p></o:p>
So..... if you want to use hydraulics to tilt the mass and you want a perfect result, you MUST maintain the steer angle in the optimum position at ALL TIMES.*.... and trust me.... you DO want hydraulics [or some other servo power] because thats the only effective control at low speeds [when a motorcycle falls over\].................... sounds like a job for a "super computer".?..... not really!!! <o:p></o:p>
<o:p> </o:p>
A freely castoring wheel [or wheel set] does it..and does it in style!!!! [see my patent] * [F.T.C.]<o:p></o:p>
<o:p> </o:p>
And so the requirement to steer and to tilt as seperate actions is gone, and now its just a simple steer control of the tilt to produce the appropriate steered path at all speeds....... its simple<o:p></o:p>

Derwin

07-09-2009, 09:24 PM

Derwin

07-09-2009, 09:31 PM

More information about this unique tilting system...

Stability simplicity.... the drawing to the right is an illustration why a FTC system can be narrow. This only describes our failsafe mode. In Fig 1 the double pointed arrow represents the controlling force applied by the driver to the vehicle tilt, the rollers under the plank represent the freedom of castoring wheels [as depicted in Fig 1a] to be able to react [steer] ..to any lateral load on the tilt mass or rotational load around the tilt axis [inertial forces].

When the mass is forced to tilt the mass naturally wants to rotate [in tilt] about its c of g. Normally in a tilting vehicle it cant do this except on a motorcycle where the rider applies countersteer manually to
the front wheel. However in FTC the front wheel/s automatically countersteer upon a simple steer input to tilt the vehicle.

Also, imagine an overturning force being applied to the vehicle ...from
outside the system [remember the tilt is restrained via the" steering input"]... so instead of the force tipping the narrow vehicle it steers the castoring wheels in the direction of the applied load.... so relieving the overturning moment. This is automatic "opposite lock" which is what a car driver has to do manually in a slide.

All done automatically ,simply by
using FTC......BUT REMEMBER... this
is only our failsafe mode of operation.

Below is figure 1 and figure 2, along with 2 images of the actual tilting mechanism...

ziggy951

07-09-2009, 10:07 PM

Most of what he says makes sense. Thats why turning and tilting must be part of a system that integrates them together at speed. Hench the reason few have built such a vehicle for more than themselves. I am surprised to find that a meter is the supposed limit of the width of such a system.

Z

WarpedOne

07-10-2009, 03:22 AM

Ok, I need more time to absorb all the details, but this quote is like listening to myself:

you don't want to steer before you tilt...... You don't even want to steer AS you tilt, because , if the steer angle gets "in front" of the tilt angle for any given speed, it will restrain the tilt, or even prevent it.. , or worse ,overcome any positive driver applied tilt and send the mass in the wrong tilt direction...or, just as bad if the steer lags too much and sends the mass too far in the right direction!!!...

That's why I don't want to have any sensors and computer controlled actuators based on sensory input. They by definiton always lag and have their internal oscilations. Because they lag, they have to work against centrifugal force that is already there and hence use lots of energy. Those can be used as a saftey backup when you loose traction and try to minimise danger/damage. Normal operation must predict the forces that will show up. Thats why my plan is to control the tilt angle soly on steer angle (of the steering wheel). This steer angle preceeds actual change in direction (and centrifugal force) because of some tire slip.