Model Boat Mayhem

The Shipyard ( Dry Dock ): Builds & Questions => Submarines => Topic started by: g4yvm on June 17, 2011, 11:30:18 pm

Title: Control of piston tanks
Post by: g4yvm on June 17, 2011, 11:30:18 pm
Quick q


 The control of the piston tanks is foxing me. Simple speed controllers to drive the motors won't stop the pistons at intermediate points will they, just run them to the end stops?  How do I control the motors to make them servo motors instead of simple spinning motors?  Is this the job of the dive controller electronics?  Does the question make sense? I want the motors to run "a bit" to drive the pistons proportionally to periscope depth, or dived or whatever... How?

D

Title: Re: Control of piston tanks
Post by: Subculture on June 18, 2011, 07:19:38 am
You use a piston tank controller!  :}

Engel do some nice ones, both proportional and bang-bang. Or you can build one youself if you're handy with a soldering iron and can follow a schematic.

You can still use a speed controller, you just fit limit switches (micro switches) at each end of the tank to cut the throat of the motor before the piston bottoms out. However the controllers aren't too expensive.

Recommend getting the book 'Model Submarine Technology' by Norbert Bruggen, which has extensive information on piston tank design and control, and is an essential tome for any budding model submariner.
Title: Re: Control of piston tanks
Post by: g4yvm on June 18, 2011, 07:31:43 am
Thanks Andy, yes I've got that book: seems to go to almost degree level on some things but doesn't clearly answer basic questions like wot I ask!

Piston tank controller eh???

Is this what microgyros dive controller system does too?

D
Title: Re: Control of piston tanks
Post by: Mankster on June 18, 2011, 10:46:58 am
The piston tank will need to be fitted with limit switches (micro switches). So the motor stops before the piston hit the extreme ends and jams/stipes a thread. Pretty easy to set up. If you want cheap and chearful you could rig a a servo and couple of microswitches in into a reversing switch to control the motor on the piston tanks. Next step up would be to use a speed controller instead of a servo/microswitch combo for finner control.
Next up is a dedicated piston tank controller which is an all electronic version of the Servo/microswitch combo (normally with some failsafes biult in - like loss of signal, low voltage).
Top of the tree is a proportional piston tank controller - where a sensor detects the position of the piston and maps it to a proportional stick / slider / knob on the Tx.
If you want to build and wire up your own rather than buy, I's go with the servo/microswitch combo and a separate loss of signal failsafe.