Off Roading adding rear wheel steering, anybody done it?

[Andres]

I'm thinking of adding rear wheel steering to my Cummins Hummer H1. I've seen the full hydraulic piston manual control types on some rockcrawlers, but I'm leaning towards a more automated system, possibly DC controlled with a small microcontroller.



I'm collecting info now and probably won't start on it until late spring. FWIW, Hummers use the same geared hubs on all four corners utilizing an independant suspension with a-arms, 2 ball joints and a tie rod. Of course in the rear, the tie rod is attached to the frame, to a center link. There is plenty of room to utilize tie rods and some sort of centerlink, the bigger battle is control systems.



In any case, has anybody done such a system or know a good source for more information? And, it of course will be disabled when on the street.



Thanks!

 

[kparker]

Why not do simple cutting brakes? You could probably get that thing to turn better that way, with a lot less engineering effort.



KP

 

[MickeyMiller]

"And, it of course will be disabled when on the street"... hell! Imagine how easy it would be to parallel park an H1 with 4 wheel steering... no more passing up those small parking spaces!!!

 

[DCreed]

what system did GM use on their Quadrasteer pick-ups?

 

[DodgeWarlock]

As I recall, it was electronically controlled full hydraulic with a max of like 5-10 degrees. It was locked out above about 5 mph. Pretty sure the cylinder had a positive stop when locked to avoid any wandering. Wish I could remember the exact specs.

 

[Loren]

As I recall, it was electronically controlled full hydraulic with a max of like 5-10 degrees. It was locked out above about 5 mph. Pretty sure the cylinder had a positive stop when locked to avoid any wandering. Wish I could remember the exact specs.

I never owned one but did read the magazine reviews carefully. (Is this like saying that I stayed at a Holiday Inn Express last night?)



The magazines reported that below some speed (about 20 mph, I think) the Quadrasteer would turn in the opposite direction to the front wheels in order to tighten the turn. Above some speed (40 mph?), the Quadrasteer would turn the same direction as the front wheels.



The logic behind turning the same direction at higher speeds is that a lane change becomes more of a sideways drift with the trailer in tow that way. With normal steering, the truck must develop a significant angle to the road in order to change lanes. With all four wheels turning the same direction, the truck stays straight with the trailer and "slides" sideways into the next lane.



I very much like the logic behind the system. I know it's complicated, but I'll bet we see something like it again as computers take over even more functions on vehicles. I wish I could get it now on a Dodge.



Loren

 

[DodgeWarlock]

Loren I defer happily. It's been a long time since I read anything about it technically. I'm definately not an expert on the subject. The few people I've met that had it loved it, but it seemed too complicated to retrofit whole system safely.

 

[Pavemen]

i know this is a few weeks old, but for wheelin, i'd want all manual control. unless you are very knowledgable about the exact response a programmed solution would have, it would be difficult I think to wheel efficiently.

placing the rear wheels is as important as the front and i think manual system would be easier to use on the trails. with programmed system you need to approach an obstacle with the knowledge of where the rear end will go as you manuever the front around.