RE: [PSUBS-MAILIST] NR-2 Thruster Arrangement

James,

You use an electronic pressure sensor and use a simple PID control circuit to maintain depth after the sub has been properly trimmed. Or dive slightly positive, and use continuous thrusters to maintain depth under electronic control. The benefit of the last is with a loss of power, you ascend (downside, uses more energy).

R/Jay

Respectfully,

Jay K. Jeffries

Andros Is., Bahamas

A skimmer afloat is but a submarine, so poorly built it will not plunge.

From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Lil Brother LLC
Sent: Thursday, July 26, 2007 7:17 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] NR-2 Thruster Arrangement

Jay,

The depth maintain is an interesting idea....hadn't thought of that. Would this be a off the hip type setting from the pilot/captain, or does the system actually know it's depth and maintain it (with exterior pressure I'm sure).

James Long
Owner/Designer
Lil Brother LLC (Instrument Division)

----- Original Message -----

From: Jay K. Jeffries

To: personal_submersibles@psubs.org

Sent: Thursday, July 26, 2007 5:55 PM

Subject: RE: [PSUBS-MAILIST] NR-2 Thruster Arrangement

Joe,

James suggestion of proportional control is on the money. Another consideration for depth control associated with a proportional joystick arrangement is an on-edge dial which is used to dial in the depth you want to maintain. This makes driving the sub underwater much easier, especially mid-water. As you know, planes and rudder control are ineffective below 2 kts. This type of control is regularly utilized on tourist submersibles and ROVs.

R/J²

Respectfully,

Jay K. Jeffries

Andros Is., Bahamas

A skimmer afloat is but a submarine, so poorly built it will not plunge.

-----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Lil Brother LLC
Sent: Thursday, July 26, 2007 6:21 PM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] NR-2 Thruster Arrangement

Joe,

I just noticed (the light finally went on) about something you posted

earlier:

"Directional control one hand....rate (current flow) the

other. Joystick back all four thrust downward for rise, joystick

forward all thrust upward for descent."

I would probably do this different. If done in the appropriate manner, the

controls could be setup proportionally. The further you pushed the

stick...the faster the movement would happen(well the more thrust in that

direction would happen).

This would simplify your controls greatly. One hand doing thruster control

(up, down, left, right, and spin about it's vertical axis), and the other

hand handling the rudder(possibly differential primary drive motors) and

primary drive motors. This does depend on the method of rudder control and

the extent that you are willing to take the control system. This would make

the system totally in both hands other than ballast control, which could be

done as well, but that can be discussed later.

This doesn't simplify the surfaced maneuvering problems of the vessel. You

could put an additional button to enable the horizontal thruster for surface

operations(this would also disable the x thrusters). Then the standard

controls could be used.

All of this sounds expensive, but it can be done much cheaper than most

people think. Hence the reason I want to help. Plus I need a project to help

with.

James Long

Owner/Designer

Lil Brother LLC (Instrument Division)