Steering via Linear Actuator

[Sparky]

I need -

Simple steering / Split rack system. 6 inch travel cylinders (X2) if
one extends, one contracts by the same amount, controlled by steering
wheel (rotary control). Always returning to "home" (center)

Cannot be a rack (which would be easier) for reasons I will explain if
needed.

I can get sylinders from one of dozens of suppliers, it is the
controls I need, programming. Cylinder suppliers say "look at our
catalogue" On board PC is available if that helps.

Sounds simple to me, anyone know where I can find someone who can help?

 

[Ecnerwal]

I need -

Simple steering / Split rack system. 6 inch travel cylinders (X2) if
one extends, one contracts by the same amount, controlled by steering
wheel (rotary control). Always returning to "home" (center)

I have a backhoe which does this - but it does not actually bother to
"extend" the cylinder that extends - if just applies pressure to the one
that pulls in, and permits the one that is extending to vent fluid back
to the reservior (through a restriction, so it doesn't flop). The ends
are attached with a chain, and the back side of the cylinders are
cross-connected, but only have air in them.

With a rigid, rather than chain, connection, you could use two push
cylinders rather than two pull cylinders.

If you really want one pushing and one pulling at the same time, it gets
tricky, as they push and pull by asymmetric amounts.

 

[Tim Wescott]

I need -

Simple steering / Split rack system. 6 inch travel cylinders (X2) if
one extends, one contracts by the same amount, controlled by steering
wheel (rotary control). Always returning to "home" (center)

Cannot be a rack (which would be easier) for reasons I will explain if
needed.

I can get sylinders from one of dozens of suppliers, it is the
controls I need, programming. Cylinder suppliers say "look at our
catalogue" On board PC is available if that helps.

Sounds simple to me, anyone know where I can find someone who can help?

Do you need the boards designed, or the programming done? Using
already-made boards is definitely cheaper for short run production if
you can live with the size.

I can do either -- contact me off list for details if you're interested.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

Do you need to implement control loops in software?
"Applied Control Theory for Embedded Systems" gives you just what it says.
See details at http://www.wescottdesign.com/actfes/actfes.html

 

[Rich Grise]

I need -

Simple steering / Split rack system. 6 inch travel cylinders (X2) if
one extends, one contracts by the same amount, controlled by steering
wheel (rotary control). Always returning to "home" (center)

Cannot be a rack (which would be easier) for reasons I will explain if
needed.

I can get sylinders from one of dozens of suppliers, it is the controls
I need, programming. Cylinder suppliers say "look at our catalogue" On
board PC is available if that helps.

Sounds simple to me, anyone know where I can find someone who can help?

Why not just one cylinder and a drag link? The last power steering
I looked had just the one.

Thanks,
Rich

 

[PeterD]

Why not just one cylinder and a drag link? The last power steering
I looked had just the one.

Thanks,
Rich

One cylinder, outputs on both ends, right?

used in tractors/earth moving equipment and... marine applications for
rudder control.

 

[Rich Grise]

One cylinder, outputs on both ends, right?

used in tractors/earth moving equipment and... marine applications for
rudder control.

The one I saw was a single-ended, albeit double-action cylinder, i.e.,
one piston rod, but with ports for "push" and "pull". It was for
power steering on a car; I have no idea how they compensated for
the different push/pull force.

Cheers!
Rich

 

[Sparky]

Cannot be a rack (which would be easier) for reasons I will explain if

needed.

Easiest way to explain the need for two linear actuators, seperate, no
drag link - pretend the left wheel being steered and the right wheel
being steered are seperated by a mile or so.