rear axle steering question

[aminnich]

I just have a question about this concept, it does not pertain to my contest build, so i made it another topic.

So i am wondering if the rear axle steering is the same as one of the front axle steering but opposite.

Also with trailers, do all of the axles have the same angles?

I hope that is understandable, thanks!

[Saberwing40k]

First part: No, and as a matter of fact the rear axles of some vehicles with all wheel steering barely move. Essentialy, the rear axle turning would reduce the vehicle's turning radius, as if the front axle turned that much farther. The rear axle can steer as much as the front one, but in most vehicles its often less.

Second part: No, trailers usually work the same way any other vehicle with multi axle steering would work. However, with trailers, like a ballast trailer, the first axle behind the truck is fixed, and then the rest steer. Contrast with 42009, which has the fixed axle in the middle.

[bonox]

Well, it depends on what you're building Saber

A monster truck or telehandler would happily take equal angles. Same with any rigid chassis capable of crab steering.

A sportscar on the other hand would have quite different values.

For the trailer, you have to think about the point about which the whole thing rotates, then the steering angles are made to keep the wheel rotating around that point. For trailers it gets tricky and they're pretty much always a stopgap value because even if the prime mover holds a constant steering angle, the turning radius of the whole assembly will keep getting smaller.

ie, they generate spirals, not circles for fixed steering input.

aminnich

aminnich - see if you can find youtube examples of a four wheel steer car (like honda prelude for example) and compare that to a telehandler and a 3 axle bus. I've seen some vids where they do a full steering lock to lock motion so you can see what happens.

The prelude also had two modes I think. A high speed one where both axles turned in the same direction and a low speed (or parking) where they turn opposite.

[aminnich]

Ok, so a truck would only have one rear steer axle and the trailer would be the opposite, only one non steering axle... right?

[Kman860]

I was going to reply but....^^these guys pretty much got it covered

[BusterHaus]

A sportscar on the other hand would have quite different values.

The prelude also had two modes I think. A high speed one where both axles turned in the same direction and a low speed (or parking) where they turn opposite.

Nissan also had a 4-wheel steering system called HICAS, and a later version called Super HICAS. It worked by taking measurements of speed, throttle and steering wheel positions. There's a very good write-up about it here. It also mentions that this type of steering was used by several other manufacturers.

I doubt this type of steering would be any use in a Lego model, as the extra weight and complexity would eliminate any handling advantages.

Here is a video showing it in "action":

[aminnich]

Thanks for all the replies, but im looking at it from a LEGO stand point, so programming is not really an option with power functions. Im just asking as a general question. And i think it has been answered

[Andy D]

I don't know if this is what you are looking for, but I recently found this thread while looking for some driven and steering options

http://www.eurobricks.com/forum/index.php?showtopic=92099&st=0

IHTH

Andy D