Steering columns are notorious for impaling drivers, or exploding their heart in collisions. Also, they are an impediment to modularity in vehicle design.
So the idea is that the steering wheel would be attached to a hydraulic pump, and two flexible hydraulic hoses would lead to a double-acting hydraulic cylinder that would replace the rack-and-pinion assembly.
Power-assist optional (and easily implemented). Left/right drive easily swapped. Driverless (computer piloted) configuration easily swapped in or out.
Failures (i.e. leaks) easily detected, and very unlikely to cause sudden complete loss of steering.-- afinehowdoyoudo, Dec 18 2014 A rack and pinion is a physical mechanical linkage. While catastrophic failures are possible, they're extremely low probability.
This approach is dependent on a hydraulic pump, which will fail in the first place. Also, while leaks might not be a huge issue, a burst hydraulic line is another story, and not exactly unlikely. Finally, spraying hydraulic fluid is not exactly much more of a friend in a wreck than a steering column.-- MechE, Dec 19 2014 //dependent on a hydraulic pump, which will fail in the first place//
Mmmmm. Most boat steering is hydraulic, and there are extremely low maintenance/failure versions of that. Twin redundant systems could easily be implemented.
I'm not saying this is a great idea, but I think the reliability could be addressed. Run a 2000PSI system with 5000PSI hoses is a good start.-- Custardguts, Dec 19 2014 What [Custardguts] said.-- 8th of 7, Dec 19 2014 Not bothering to look this up, but have a sneaking suspicion Citroen may have monkeyed around with this..-- not_morrison_rm, Dec 19 2014 It's probably cheaper and easier and safer to use electrical rather than hydraulic control.
If you argue that (hardwired) electronics are more fault-prone than hydraulics, I'd question that. But, more to the point, you can have fourfold redundancy in an electric circuit for less than the cost of twofold redundancy in hydraulics.-- MaxwellBuchanan, Dec 19 2014 Electric power steering is totally baked, has complete industry confidence, and has notable advantages with regard to selectable effort ratios. Whereas the notoriously hyraulicophillic aircraft industry is already going electric.-- bs0u0155, Dec 19 2014 <Hooper>
"Hahaha, they're all gonna die …
</Hooper>
Hydraulics good, electrics … very bad.
// car companies and putting animals under the bonnet ? //
Well, they've been putting them behind the steering wheel since automobiles were invented …-- 8th of 7, Dec 19 2014 I first read thus as a system where the steering wheel controlled hydraulic pumps making a drive- by-hose system. On more careful reading, I think the idea is to have the steering wheel turn the hydraulic pump. Assuming a reversible positive displacement pump, that would automatically provide feedback to the driver, just like a mechanical connection. Also, it could operate when the engine is off, just like power assist brakes.
Considering that we trust hydraulic brake, steering doesn't seem like too much of a stretch, but I wonder might result in too much play in the steering. In brakes, if you have a tiny air bubble, it makes the brakes a little soft and less responsive, but generally that isn't serious. However a small air bubble in hydraulic steering would make the steering springy. Also, brakes lend themselves to an efficient redundant system because a car can have two wheels on each hydraulic system, making the only overhead be the slightly more complex master cylinder. When one fails, braking performance is reduced but still works. For steering, making the system redundant seems harder to do efficiently. I can't think of any way that steering performance can be reduced that is acceptable, so both redundant systems must be fully capable by themselves.
I generally like electronics, but in this case it seems a little iffy. I'm all for electric assist, but if a failure of the electrical system will cause me to loose steering control entirely, I'd be worried. Therefore we'd need a whole backup electrical system complete with a second battery.-- scad mientist, Dec 19 2014 Close all the windows and restart?-- popbottle, Dec 20 2014 Electric power steering is burnt to a crisp. Power steering pumps are burnt even crispier, and collapsable steering columns are deep-fried. What's new here besides having a horrible system with no road feel?-- RayfordSteele, Dec 20 2014 But....you could have the steering wheel in the back seat. How cool would that be?
PS. pure hydraulic steering is found on articulated front loaders, and fork-lifts.-- Ling, Dec 20 2014 ^ and articulating dump trucks.<side note> they are made to rotate longitudinally as well as articulate side to side in case the load tips. I found out the hard way. Ended up half-in half-out of the passenger window......good times.-- 2 fries shy of a happy meal, Dec 20 2014 //you could have the steering wheel in the back seat.
like th Viz cartoon asking why the driver gets to sit at the front, while the paying passengers have to sit behind him/her-- not_morrison_rm, Dec 20 2014 A double-decker bus coud be driven from the upper deck. That woud help reduce bridge strikes from "stray" buses ...
It would also allow improvements in disabled access.-- 8th of 7, Dec 20 2014 Electromechanical steering is considered the newest and best technology. Solid state with no moving parts, no pumps or pipes that can leak, etc.-- sanman, Dec 23 2014 //no moving parts// so hw does that work? An electromagnetic field constraining a shoe that slides along the road surface?-- pocmloc, Dec 24 2014 random, halfbakery