Thoughts about throttle controls. Cable vs Servo

Refueler

Refueler

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Being an RC addict .. I use servos from tiny 3gr up to large that control models .... with torque that really means they can operate many items - such as throttle or even gearboxes.

With damaged throttle control cable on my MoBo and previous to that - the gearbox cable shredding on my Motor Sailer .. thoughts of using large RC servo have crossed my mind. Throttle control would not take such a large servo .. but the operating arm would need to be long enough to get reasonable arc for sensible throttle setting.

We have non Radio controllers for testing servos ... basically a pot on a board ... so the control lever part could be easily made.

I presume that already there are wireless or electronic marine controls ... no doubt at 'marine prices' ...

For my setup - IF I was to do it ... I think I would leave the gearbox on Morse cable lever and put just throttle to servo control. That way the installation is simple ...

Its actually not likely I would do this - but interesting concept.
 
It was more a train of thought exercise .. and I am not surprised that an avenue has been already ..

I would hate to see the pricing though !! When I consider that with a suitable servo ... cables .... servo tester control .... BEC converting 12v to 6V to power it ... would be less than 50 quid ..

Of course refining the design of control lever would be needed ...
 
Stemar said:
Indeed. I reckon it would be a lot easier to bodge a morse control/cable setup than RC and servos when things get "interesting", unless you go full aviation mode with complete triple redundancy so it can't.
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mmmmm when you consider what we ask servos to do .... off-road cars ... boats .... waterplanes ..... and some of these are not small toy size !

mmmmmmmm bodge a cable setup ... knowing the physical layout of the mobo I am at present having to replace the throttle cable .. I am hesitant as to whether it would be that easy to bodge a setup ...

But discussion should continue - it was started as conversation item ... who knows what may result ..
 
As with homegrown plotters the stumbling block might be waterproofing the control. I can’t see anything wrong with the theory and failure mode would be identical to a cable. Probably easier as there’s no cable to prevent movement.
 
Refueler said:
mmmmm when you consider what we ask servos to do .... off-road cars ... boats .... waterplanes ..... and some of these are not small toy size !

mmmmmmmm bodge a cable setup ... knowing the physical layout of the mobo I am at present having to replace the throttle cable .. I am hesitant as to whether it would be that easy to bodge a setup ...

But discussion should continue - it was started as conversation item ... who knows what may result ..
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Have a look at the MAIB report on MT Prospero.

Failure of podded propulsor system on chemical/products tanker Prospero and subsequent contact with jetty

You should enjoy it as it involves loss of control of an ill thought out, badly executed and poorly maintained very modern tanker...and it's sister tships too!

Systems designed, built and supplied by Siemens, no less.
 
seeSimon said:
Have a look at the MAIB report on MT Prospero.

Failure of podded propulsor system on chemical/products tanker Prospero and subsequent contact with jetty

You should enjoy it as it involves loss of control of an ill thought out, badly executed and poorly maintained very modern tanker...and it's sister tships too!

Systems designed, built and supplied by Siemens, no less.
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Apprecaited the link ... but TBH - its a far more sophisticated and ill thought out system than I am talking about.

Interesting though .. some may ber interested to know ..

The controls of many vessels .. that includes Passenger / Container / Bulk and Tankers - have for many years had possibility to include bridge wing panels. The standard wheelhouse telegraph / bow thruster controls being duplicated on each wing ... The Pod design has used that concept.
I sailed on 900 ton up to 440,000 ton tankers that used such ... but most Masters / Pilots declined using. Partly because of accountability. But Bridge control of engines etc has been accepted widely. The engineers basically providing watch over the system and ready to take over executing commands manually if needed.

All movements of vessels when in confined waters and manouevring are required by Owners and standards of Maritime conduct to record in the 'Movement Book' all commands given. To facilitate reconstruction of events if incident occurs.
 
Refueler said:
My starting the discussion was purely out of interest and to see if anyone had ideas / creating a discussion ..

If the Hammer was always put down ... where would we be today ? Still living in caves ??
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I don’t suggest always putting it down. The hammer is an irreplaceable tool.
 
When I read reviews of Auto Trim Tabs on Mobos .. where some leading brands use the same gear as we use in drones for autonomous flight / auto-levelling etc ... the level of electronics far exceeds what I am talking here.

What would do the job ... just discussing - not proposing !

Decent waterproof or Corr X protected servo .... decent torque figure of lets say about 1kg ... arc od travel ~150 deg ... time over full arc ~0.1sec ? Plenty of servos out there for small money. Say about $30

Servo tester with full arc pot control ... $10 but lets go a bit upmarket ... $20

DC-DC reducer ... dropping your 12 - 14V supply to a steady 5v or 6v for the tester / servo. $5 .. but again - lets go upmarket a bit $10

3 strand cable (signal. +, - ) for tester to servo ..... about $5 a metre. Few gold crimp plugs designed for the cables ... $5

Bit of music wire to connect servo arm to throttle linkage.

Metal plate to mount servo on.

As a test setup - the rotary pot on the tester will be fine to prove the control works. To have as a usable control - then the pot would be replaced with a lever - to allow due to its longer length - finer control of throttle.

As I said though .. purely a concept discussion idea.

When you think about people using Pi boards etc ... is it really that unreasonable ?
 
As a slight drift but a little bit of a slightly relevant input;-
As a Sea Cadet officer, I chartered two boats out of Falmouth for a bunch of "mixed ability" cadets. My wife and I had one and the other was skippered by a RNLI member with a works colleague of mine as mate.
The weather was grim and we were fog bound for three days. Avoiding referencing the near riot when the crew went ashore, we eventually departed for Alderney.
Mid channel, wife was on the helm when she reported the boat was not answering.
As I turned the wheel, I could feel something "cogging". Not sure that is a valid word but the tactile sense was that a gear somewhere was engaging and disengaging.
There was a gearbox at the head of the steering pedestal.
There was another at the bottom of the pedestal leading outboard.
There was another at the side of the hull leading aft.
There was another aft back to the centre line and the final one feeding the steering quadrant.
At each gearbox the fingers and the ears declared that that was the culprit. The clicks travelled along the whole linkage making diagnosis impossible.
An "all ships" call advising of our predicament produced no response (not even from our other boat).
Arriving in Alderney, gingerly nursing the gear train, we found a buoy which I lunged for it, cracking a rib.
The crew were repatriated by air (which made their trip!) and we returned on the other boat.

That is why I have cable steering, visible and accessible along the whole length of the transmission.
In the event of total failure, two bits of rope may serve.
KISS springs to mind.
 
Fly by wire has been implemented in numerous production vehicles, not just aircraft so as a concept it's a well worn path.

Yamaha have used it for throttle control on the R1 motorbike since 2007!

The components involved are all very well known and understood, and can have extremely good reliability, so system reliability will be down to the implementation really.
 
I do not intend to implement on any boat I have - but because I have the items on my bench - I may just connect up some gear and see how it would fair ...

The concept is not a problem ... what is - the physical part of creating a suitable lever design controller ... and the fixing of the servo to the engine.
 
Refueler said:
Wtaerproofing is no problem at all ... we already have waterproof servos etc.

For all - a dose of Corrosion X adds as well.
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Was thinking throttle end but now I realise (I think) you’re intending to connect to the existing throttle control inside? If so, that sounds really rather good
 
lustyd said:
Was thinking throttle end but now I realise (I think) you’re intending to connect to the existing throttle control inside? If so, that sounds really rather good
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Haven't actually intended anything .... it really is just a conversation piece ..

If you are thinking that I thought of using the existing throttle lever - no I hadn't ... the problem would be that the lever has to be able to turn in both directions ... FWD / Astern ... but the controller will only allow one way rotation for throttle function.
It would be necessary to have the throttle function separate to the existing lever ...

The basic idea :

Rotary controller at the helm to alter throttle.
Servo mounted on bracket linked to the engine throttle linkage.
 
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