Recently when searching the web for inspiration I found the Toyota iRoad Concept, and decided I'd give building it a go.

The steering was what got me interested in this machine, just because it's a bit different. I've designed a simple chassis for it on LDD which is a long way away from the final design, but before I do anything else, I would like to know if the chassis design would work, however I do not have the sufficient parts so I was wondering if anyone would build it for me, and show it as a built chassis. I've got some pictures of the design and I can upload the LXF file as long as someone can explain how to.

Thanks,

cgg199

Edited December 15, 201311 yr by cgg199

I think the rear tyre is too wide and flat. Probably the chassis would be 'straight' and wouldn't 'bend over' while trying to turn.

Greets,

Fresko

Edited December 15, 201311 yr by fresko

Hi,

I don't get the steering. Can you post better images from different angles. It might need a narrower rear tyre. I see what you're trying to acheive though (just googled iroad concept).

H

I agree with what you're saying. In realty, it would need a motorcycle tyre on the back so allow the vehicle to lean when cornering.

When turning, the inside wheel lifts up to cause the vehicle to tilt / lean in the direction you want to go, forcing the vehicle that way. In the photo above, the wheel on the right hand side has been raised, which would cause the vehicle to lean and turn.

Another photo where the inside wheel has been lifted to steer the vehicle.

The problem is, Lego don't make a rounded tyre the same size as the rear, so my options are...

- Use that wheel and not allow the vehicle to function properly.

- Position two Wedge Belt Wheels (4185) along side each other, allowing the vehicle to turn properly.

Oh, I best upload a photo of the real thing as well.

Edited December 15, 201311 yr by cgg199

Wow, that's pretty cool! I actually thought about building something like that once, but never got around to it. I'm looking forward to the result.

Thanks, it's a bit different from most vehicles so I thought I'd give it a go!

How does this look for a rear wheel? It's narrower and should be better than the previous design.

Cool, but I think the front wheels are also supposed to turn, not just lift up.

Cool, but I think the front wheels are also supposed to turn, not just lift up.

They stay fixed. It's the rear wheel that turns, you can see its cowling in the first real picture.

Good concept, have fun figuring out what I've just pointed out! Do it!

i think that

1 it's a cool idea!

2 you should try the rear wheels of the pullback buggy

I am not sure leaning is what makes it turn. I would rather say leaning is a consequence of turning i.e., the vehicle 'leans because it turns' and no 'must lean in order to turn'. To make the vehicle turn, you need to provide different speeds to the inner/outer wheels. In my opinion, the tilt is there to make sure the vehicle does not tip off when taking a turn (to counter centrifugal force). The Toyota vehicle looks just like a competition motorbike, with two front tires ipo just one, and those motorbikes tend to lean on the inside to make a turn, otherwise they'll fly away.

it's a rear tyre turned on that picture? in my opinion "yes"...

The Carver One would suit piterx colour and style and would impress guys at lego, the leaning on these vehicles will be tricky to do because on the real thing its computer controlled.

this guy did that! and it works amazingly well without computer control :D

this guy did that! and it works amazingly well without computer control :D

I wonder how well that contraption handles turns at high speeds ...

Also, and in real life, the amount of tilt would depend on two parameters: The steering radius (how aggressive the turn is) and the vehicle speed. The first can be easily achieved mechanically, but for the second, you definitely need a computer. In contrast with motor-bikes, the driver cannot lean (to offset the effect of his weight) and stabilize the vehicle ...

Edited December 16, 201311 yr by DrJB

Well it's good to know that I have started building something that I don't understand! I've sorted it out now, and the rear wheel turns as well as the lifting of the front wheel, all controlled by the steering wheel. Here's a picture.

The 3x3 thin liftarms (pink) pull the grey track rod forwards and backwards causing the rear wheel to turn. Not a great description but I hope you get the idea.

Also, thanks Piterx, that wheel and tyre will work a lot better.

Very cool project, I'm very interested by LEGO 3 wheelers. I shall stay tuned!

Quick photo to show the finished vehicle. It isn't quite complete because of LDD not allowing me to sort out the flex cables.

A motorcycle wheel should do the trick, infact I would make all three wheels motorcycle wheels. To me it looks like your main problem will be keeping the outside front wheel in contact with the ground during the leaning/turning process.

That's a tricky one but i'm sure it can be acheived.

H

Also, and in real life, the amount of tilt would depend on two parameters: The steering radius (how aggressive the turn is) and the vehicle speed. The first can be easily achieved mechanically, but for the second, you definitely need a computer.....

Not so! Airplanes have had mechanical ratio changers for years. For example, on some commercial aircraft the ratio between the movement of the rudder pedals and the movement of the rudder itself is a function of airspeed. This is to prevent too much rudder motion at high speed. The system is entirely mechanical and based on dynamic air pressure. For a vehicle like this, I can imagine some kind of flywheel that changes the gear ratio to the tilt as a function of wheel speed.

A motorcycle wheel should do the trick, infact I would make all three wheels motorcycle wheels. To me it looks like your main problem will be keeping the outside front wheel in contact with the ground during the leaning/turning process.

That's a tricky one but i'm sure it can be acheived.

H

If I use motorbike wheels, the vehicle will be really tall and odd looking. There aren't any motorcycle wheels of this scale unfortunately.

Now I present the Toyota iRoad Concept.

And I would just like to say a huge thank you to Piterx for helping me with the body!

you need another small light under the big one :P

and there's something with the rear part that makes it look strange...dont know what it is :P

Thanks for those pieces of info. I really should take a closer look at some pictures.

I'm not entirely sure what to do with the back, the real one is rounded but I don't think I'll be able to do that.

The new front light

Edited December 16, 201311 yr by cgg199

Neat!

Not so! Airplanes have had mechanical ratio changers for years. For example, on some commercial aircraft the ratio between the movement of the rudder pedals and the movement of the rudder itself is a function of airspeed. This is to prevent too much rudder motion at high speed. The system is entirely mechanical and based on dynamic air pressure. For a vehicle like this, I can imagine some kind of flywheel that changes the gear ratio to the tilt as a function of wheel speed.

It seems we have few passionate engineers on the board here, which is a good thing. I'll rephrase my statement and say that the tilt as a function of speed cannot be achieved EASILY by pure mechanical means. The reason airplanes can 'afford' such fancy mechanics is for several reasons: at least years ago, mechanical systems were deemed more 'reliable' in terms of their performance/behavior ... Nonetheless, and back on topic ... in this modern day and age (features such as RSC, AdvanceTrack, and others available on cars) I highly doubt the Toyota has a full mechanical tilt vs. steer vs. speed mechanism ... I'd love to learn otherwise though, as I'm sure a mechanical solution is always more elegant than a mixed one ... and at least it could be reproduced with lego. Cheers.

Edited December 16, 201311 yr by DrJB

My system probably has no similarities with the Toyota one. I haven't looked at the system in any detail, just what it does, and replicated it using Lego, my own way.