Tilting cargo trike steering??

[jawnn]

I was reading about Ackerman steering and wonder if there is any diffence in tilting cargo trike steering.

It will be long one simular to the one on Instructables. He says nothing about the steering.

Got any ideas?

It will be saturday before I get back here, the library will be closed.

[Mark Kelly]

Yes they are completely different and intended to accomplish different things.

"Ackerman" steering is intended to accommodate the fact that a vehicle turns around the inside non-steered wheel.

Tilt steering is intended to reduce steering effort using mechanical positive feedback.

[jawnn]

so what do you think, is there a way to improve this steering??
tilting-trike1.jpg

Yes they are completely different and intended to accomplish different things.

"Ackerman" steering is intended to accommodate the fact that a vehicle turns around the inside non-steered wheel.

Tilt steering is intended to reduce steering effort using mechanical positive feedback.

[Mark Kelly]

so what do you think, is there a way to improve this steering??
tilting-trike1.jpg

I'm sure there is and I'm sure you'll work it out when you do the research.

[bencooper]

Biggest problem I can see in that pic is it's not centre-point steering, so it will bump-steer like mad. The usual method is to angle the kingpins so they point to a point in front of the contact patch. The tilting makes that trickier, of course.

[jawnn]

I plan to make it about a 2" trial... I will do more reading.


tilting-trike1.jpg

[jawnn]

Ok, the Ackerman steering was bit confusing but I visualized how down hill skyers turn a sharp corner. the result was this , it will do the same thing that Ackerman steering does.

I am thinking the cams maybe a bit unnecessary, how much can the wheel on the out side be pushed back on trike? I am thinking only abut half an inch, so maybe the cam would be no bigger than one quarter inch? Wish I had a computer program to calculate it all. (the steering tie rod would turn the out side wheel 'tow out' when it is pushed out.)

front end of trike.jpg

And one half inch tail is a better idea. Now wheel flop.
half inch trail.jpg

Does any one know about this cam concept?

[jawnn]

This is the Tripendo tilting trike Two separate suspensions?


tripindo front end.gif

[Mike Mcdermid]

you might want to look at a tractor for inspiration that combines massive tillt and centre of and trail

you can download excel sheets that will do some rudimentary ackerman setups they wont take into account bump or over under Cof g centrsteer etc like an automotive setup but its rudimentary starting bump droop camber caster etc i had one somewhere that did all this

in fact theres a link i dropped on by typing ackerman excel Peter Eland's site: Ackermann steering spreadsheet

[jawnn]

Maybe if I just build a model out of paper.....this is not Ackerman steering.

Actually I think the idea of the cams will not work.


I would really like to find some that has done this kind of steering.

[drwelby]

Have you seen the ? Saul Griffith discusses the steering challenges around 2:20.

[Mike Mcdermid]

Maybe if I just build a model out of paper.....this is not Ackerman steering.

Actually I think the idea of the cams will not work.


I would really like to find some that has done this kind of steering.

Maybe build a paper model anything that gets you an understanding

It might not be ackerman but you wanting to learn or someone to just hand you a solution on a plate you can tweak and call your own

[Mike Mcdermid]

Have you seen the ? Saul Griffith discusses the steering challenges around 2:20.

Similar to offroad earth moving tractors that pull a scraper

[jawnn]

Too bad they don't just hold the picture still. But they did sy that the out side wheel has to steer more thenthe inside, but HOW?

Why is this stuff just not on the net to see in a detail diagram. It looks like the top suport arms should be a bit shorterr than the bottom.

so how do I messure it?
tilt steering.jpg

[bencooper]

That's Ackerman geometry. To set it up:

Imagine a line drawn through the kingpin and the steering rod pivot. That line should intersect the rear wheel's contact point.

That's the simplest method, though it only works if the inboard steering rod pivots are very close to each other.

[jawnn]

I am starting to think there just is not any way to make titled steering do this. Unless it is just a big secret.

steeri9.jpg

[jawnn]

does any one know why this will not work for the front?

black max tilt mech.jpg

[bencooper]

As I said before, it's because you don't have centre-point steering - the axis of the kingpins doesn't point to the track of the front wheels. It needs to be angled so it points to a position an inch or two in front of the contact point.

So you have two issues to sort - angle the kingpins (and design it so they stay angled when the trike leans), and sort the steering linkages so the inner wheel follows a smaller radius to the outer wheel.

Definitely possible to do both.

[Gattonero]

Is the tilting steering meant to be used on a Cargo or a normal trike?

I do remember the Nihola trike, which used an articulated steering. Interesting and fairly well done, but impractical due to the trike geometry and the lack of camber in the wheels.
Different approach from Christiania, where the trike has the whole front frame (carrying the wheels) that moves on an angled steerer, so that when turning the trike does get positive feedback and gets easier to move

Btw, if Cargo is, I may suggest you:
-use "handle" style bars, not common bars. Having bars that hold the cargo box at both ends helps a lot
-give camber to the wheels!
-wheelbase seems pretty long (see below)
-steering wheels won't entirely sort the problem of big turning radius of the whole trike
-steering wheels need space to move, hence the cargo box has to be narrow
-the joints for steering add weight and maintenance, and labor+materials. IMHO not worht at all, but it's up to you

[bencooper]

I do remember the Nihola trike, which used an articulated steering. Interesting and fairly well done, but impractical due to the trike geometry and the lack of camber in the wheels.

I've used both extensively - the Nihola's steering is a lot better than the Christiania's unless you want maximum low-speed manoeuvrability. The Christiania can turn a very sharp corner, but it behaves very oddly at speed, and the inertia of the load can cause some very interesting effects. The Nihola uses proper centre-point full-Ackerman steering so behaves much more normally.

Camber is unnecessary on these trikes, and only adds complication - the point of camber is to add strength for cornering (but 20" wheels are plenty strong enough) and to reduce the total width without reducing the track width.