[PSUBS-MAILIST] Speed controllers

Sat May 7 23:25:34 EDT 2016

Alec,some joy sticks have the " click to center" option, where it doesn't spring to center but clicks into a slot & requires more force to move it out.This was one of the configurable options Apem offered from memory.   I would have thought a potentiometer type joystick would be as easy to implement as any other control. What sort of input does the Minnkota controllerrequire?   I am not 100% following you, but if you are having controls out the side of thebox, you could have two joysticks with X&Y axis out either side,  & you would then turn the sub like turning the handlebars on a bike & push the other axis up to go up & down for (you guessed it) down. Crabbing you just lift up on one side & down on the other. Cheers Alan

      From: Alec Smyth via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Sunday, May 8, 2016 2:30 PM
 Subject: Re: [PSUBS-MAILIST] Speed controllers

Oh wow, Pete, you put way too much effort into that! Actually I have yet another evolution of this if I haven't tired you all yet. I like the joystick concept but its hard to implement satisfactorily without any signal processing. I also like the "tractor control" paradigm for the stern thrusters, but not so much for the side ones. Regarding the issue of spring return, I think that is intuitive for a joystick but the opposite is true for the "dual throttle" method. The latter is exactly like double throttling any boat - who would want to have to hold the throttles the whole time? So here's the new variant...
The rear thrusters will be controlled using tractor control using two pot handles coming out the sides of the box as mentioned earlier, but for the side thrusters we have two controls on the box surface. One is a speed control (knob, thumb-wheel, whatever) that controls the speed of both side thrusters. They will always run at equal speed, as they did on Snoopy. Next to it is a three position toggle switch. The center position is labeled "normal" and in that setting both side thrusters pull the same way. The left position on the toggle is labelled "Crab L" and what it does is reverse the polarity of one thruster, causing the boat to crab left. Likewise the right position is for crabbing right. Ninety percent of the time the toggle will live in normal mode and the controls are reduced to a bare minimum - two throttles for steering in a horizontal plane plus the "depth knob". It passes the test of being drive-able by a 5 year old. But the crabbing function is still there if you need it, for instance, for maneuvering onto the trailer. With this, finally, I think there is something that is just as easy to use as a joystick, yet also adheres to the KISS design philosophy of the boat. 

Thanks,

Alec
On Sat, May 7, 2016 at 7:14 PM, Pete Niedermayr via Personal_Submersibles <personal_submersibles at psubs.org> wrote:

What about something like this.

      From: Jon Wallace via Personal_Submersibles <personal_submersibles at psubs.org>
 To: Personal Submersibles General Discussion <personal_submersibles at psubs.org> 
 Sent: Friday, May 6, 2016 10:43 PM
 Subject: Re: [PSUBS-MAILIST] Speed controllers

I'm a proponent of spring return joysticks also.  I considered 
non-return ones early on but rejected them just on a perceived need 
(real or not) to have them quickly return to a dead zone instead of 
fumbling to find that dead zone if I was in a hurry to stop propulsion.  
Assuming there's no throttle feedback to indicate where center is, 
you'll need a relatively large dead band (or zone) to not overshoot the 
center position.  I've never been a fan of Z-axis though because I 
personally do not find them comfortable or user-friendly even with a 
large joystick for a computer.  There's something about twisting motion 
that is fatiguing and this would be especially true on a small diameter 
joystick.

The degrees of joystick movement is not as important as the 
potentiometer value controlling the signal to the controller.  You can 
find joysticks with different potentiometer values to get the fine 
control you need.  The more expensive joysticks use hall sensors (I 
believe) to get past this issue.  One problem I see with a mechanical 
KISS approach for components is that the UI ultimately begins to 
suffer.  Instead of one or two joysticks, extreme KISS requires four to 
accomplish tractoring and crabbing which means both hands on controls.  
I think potentiometers in this configuration are going to be less 
intuitive and more complex to operate, relatively speaking, than 
joysticks.  Think Etch-a-Sketch, and I was never good at that.  
Mechanical KISS ultimately equates to more buttons/levers/switches than 
a fly-by-wire design.  Yes, at a component level mechanical KISS has the 
benefit of being able to target a single switch for replacement but 
nothing is free and the UI becomes more complex because the user has to 
control multiple components simultaneously to perform a certain task.

Back to the Z-axis, I think if I were to use one I would give up 
crabbing and use the Z-axis simply for vertical movement.  Twist left 
for down, right for up.  I'm not sure there is a lot of use for crabbing 
in something that is not a Deep-Worker type vessel, but I do plan on 
implementing it for my sub.

Jon
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