RE: (ET) linear actuator power steering?

["Markus Lorch" <mlorch vt edu>]

You know, if I had infinite time I'd try to do it as follows

- leave all the ET components where they are (motor etc)
- control steering with a joy stick (via lin. actuator)
- increase max. steering angle to almost 90 deg
- make seat such that it can swivel and point backwards
- mount mower deck at the rear
- add some foot rests and a second speed  control and brake mech.
  at the rear

-> should be a convertable garden tractor that can turn into a
(almost) zero turn mower .... not sure how easy it would turn with
the standard differential. If that would be come a problem then two
independent drive motors (like on the Electrix Ox) could do the trick.

Markus


> -----Original Message-----
> From: elec-trak-bounces cosmos phy tufts edu 
> [mailto:elec-trak-bounces cosmos phy tufts edu] On Behalf Of jim leuba
> Sent: Wednesday, June 30, 2004 5:53 PM
> To: Herb Crary
> Cc: Elec-trak Mail List
> Subject: (ET) linear actuator power steering?
> 
> 
> Why not just a toggle switch to control the linear actuator right or 
> left.  If the switch was wired to brake the DC motor when off, the 
> actuator positioning would be pretty crisp (no drift).  
> Steering would 
> be like on a Dozer.
> 
> My E20 has worn steering gears, I have been looking for a linear 
> actuator to replace the steering mechanism with.
> 
> The other way to go would be to eliminate the entire drive train and 
> replace the front wheels  with 2 hub motors and 2 PWM motor 
> controllers 
> and replace the back wheels with 2 swivel wheels.  Then the steering 
> would controlled by varying the speed of the 2 hub motors using a 
> joystick.  Essentially "zero steer" control.  No belts, no 
> transmission, 
> no relays, and better steering control.
> 
> Jim Leuba
> 
> 
> Herb Crary wrote:
> 
> > A good source for all manner of items, including linear 
> actuators, is:
> > 
> > http://www.herbach.com/Merchant2/merchant.mv?
> > 
> > This link is to their search page. I have been buying from 
> them since 
> > i was in college in the late 1940's. They had lots of WWII surplus 
> > then. They have both new and surplus now.
> > 
> > Herb Crary
> > Boulder CO
> > E10M
> > 
> > ----- Original Message -----
> > From: "Pieter" <pvcl plitch com>
> > To: "Elec-Trak Tractor" <elec-trak cosmos phy tufts edu>
> > Sent: Monday, June 28, 2004 2:39 PM
> > Subject: (ET) power steering?
> > 
> > 
> > 
> >>All this discussion of using linear actuators as front or 
> rear lifts 
> >>got
> > 
> > me
> > 
> >>thinking.
> >>
> >>My E-15 has a very heavy loader on it, and the steering is 
> a real two 
> >>handed job.  I was looking around the 'net for info on linear 
> >>actuators to use for a lift and came across an article on an old 
> >>Yanmar diesel tractor converted to electric.
> >>
> >>http://www.angelfire.com/ca4/renewables/tracpage.html
> >>
> >>Well - why not do the same thing to an ET??  He used a 
> linear actuator 
> >>controlled by a joystick of sorts to steer.  It would be a simple 
> >>matter
> > 
> > to
> > 
> >>place a linear actuator between the frame and a steering knuckle 
> >>parallel to the tie rod.  I don't think too much force would be 
> >>required, which is good because you want fairly fast 
> response (screw 
> >>travel), so leverage
> > 
> > will
> > 
> >>be reduced.  There are a number of dish positioners that run on 36 
> >>volts and use a revolution counting circuit to stop at a 
> predetermined 
> >>position.  If the steering wheel ran an encoder that "told" the 
> >>actuator where you were pointing it, the actuator would 
> then move to 
> >>that position, steering the front wheels.  A dish 
> positioner would be 
> >>very cheap to try.  The hardest part for me to design is 
> the steering 
> >>wheel encoding mechanism.  Any engineers out there?
> >>
> >>
> >>
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> > 
> > 
> > 
> > 
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