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Re: [PSUBS-MAILIST] dive plane control scheme



Thanks Rick. Yeah - I know about PID controllers, but actually, this would all work with proportional only control, apart from the rate control for avoiding target depth overshoot. That could be PID, but I wonder if doing some tests and establishing a lookup table would be more robust? PID would be well suited for controlling the ballast system, though. There are applications out there which purport to determine the optimum tuning for any PID system, which might be a better route than trial and error. Do you have any experience with this? Rather than using distributed control, I was thinking that all systems might be controlled by a central computer with a backup, since those are required anyway for other navigation functions, cameras, etc. I don't know what the relative expense would be, but maybe there are important reasons for going distributed? I don't know - I'm a mechanical guy, and my controls background is limited. Also, I wonder if individual servomotors might be a viable alternative to a high pressure hydraulic pump and four actuators? Higher initial expense but less current draw, perhaps?

Good thoughts.

-Sean


rick miller wrote:

Sean:

The control system that you describe could be implemented with a plc that has pid controllers built in to the software.a pid controller varies its output based upon the speed at which the change to the set point is happening , the distance from the set point and the and the time that the system has been away from the set point. Pid stands for proportional, integral, derivative. Extreame care should be taken when tuning these controllers as they can become unstable durring tuning and run away.

ebaying some used parts and software you would be able to do this control system under about 5000.00$. The only trick is to use a precharged resivor that is in excess of the operational depth of the sub. That allows for the hyd rams to be placed out side the hull. There are several types of feed back systems that you could use. The best for this application would be a feed back system for a rotary actuator that could be place into a oil filled casing, side wire would be the cheapest

rick m






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