Electronic Foil Control Systems.

[dougculnane]

For another thread but this is very worthy of its own. So I started it.

 

[PorVida]

Well aside from the typical hype to which we are exposed around the world of foiling boats, especially those of the type such as the Moth, this development of the electronically controlled foil system by Clive Everest is a breath of fresh air.

I hope to hear more about it, its further development and how it will fit into the existing boat classes (or not) in the future.

Chris Ostlind

Lunada Design

www.lunadadesign.com

 

[dougculnane]

Electronics are banned from the Moth and I think all (ISAF classes) so it is just a side show. However I feel that it has such great potential to increase the control of the boats it will be hard to ignore.

Electronics have the ability to know if the boat is going up or down and how fast. The present systems just know how high it is now. The cost of such systems is potentially high but the complexity of them is nothing compared to the electronics in everyone's car, video, lift, wrist watch, fridge or electronic toothbrush.

As Clive indicated you can adjust the parameters on the water... So you have the chance to select the right configuration parameters, for chop, flat water, learner, sport mode etc... like your car.

Clive what are your thoughts about the future of such systems? Do you think they have a place in the sailing world and will this involve new classes or modificatins to the rules of old classes?

 

[Doug Lord]

Clive, very interesting design and congratulations on some terrific development work.

I'm most interested in your opinion of the various altitude sensors that could be used in this application-ultrasound ,micro radar etc.

Thanks for having the guts, courage and determination to make such a trmendous contribution to foiler development!

 

[Kevin Schultz]

Clive, very interesting design and congratulations on some terrific development work.I'm most interested in your opinion of the various altitude sensors that could be used in this application-ultrasound ,micro radar etc.

Thanks for having the guts, courage and determination to make such a trmendous contribution to foiler development!

Over thinking it, go with a 3 axis accelerometer and a contact switch. You know when you are on the surface, integrate the acceleration twice and you have height off the water. It should be a lot less expensive than either other option, plus you won't have to filter out the waves.

Interested to see what his solution was.

 

[kprice]

Electronics are banned from the Moth and I think all (ISAF classes) so it is just a side show. However I feel that it has such great potential to increase the control of the boats it will be hard to ignore.
Electronics have the ability to know if the boat is going up or down and how fast. The present systems just know how high it is now. The cost of such systems is potentially high but the complexity of them is nothing compared to the electronics in everyone's car, video, lift, wrist watch, fridge or electronic toothbrush.

As Clive indicated you can adjust the parameters on the water... So you have the chance to select the right configuration parameters, for chop, flat water, learner, sport mode etc... like your car.

Clive what are your thoughts about the future of such systems? Do you think they have a place in the sailing world and will this involve new classes or modificatins to the rules of old classes?

Electronics are banned but what about fluidic logic?

http://en.wikipedia.org/wiki/Fluidics

 

[BalticBandit]

Electronics are banned but what about fluidic logic?
http://en.wikipedia.org/wiki/Fluidics

The problem with fluidics is that you still need a hefty power system of some sort to drive the flap itself.

Note BTW, while Clive has done something very cool, 5 hours of sailing time is rather minimal for sorting out durability and other issues. Remember that at a major regattae, you can crank out 5 hrs of sailing time in one day. And a control system that lasts but a week isn't going to cut it.

BTW, an accelerometer won't really give you accurate readings since you aren't accounting for the hysteresis in the system from the foils. What you really want are are LED (low power) distance sensors, with which you can sense

• Wavetop distance
  
• Waveface slope
  
• Ride height above surface
  
• velocity of approaching waveface
  

 

[kprice]

in the other thread BB said

"That said, I don't see that the electronic control system in place is doing anything that could not be mirrored through a mechanical linkage. In essence the electronic system provides an easier means of controlling damping rates"

Clive mentioned two other sensors besides the wand so he can get

1. height by the wand

2. pitch attitude by the gyro

3. acceleration from the accelerometer (duh!)

and close the loops around each to keep height at a target, minimize pitch changes, counter unwanted acceleration, etc.

More information should mean better control.

It seems one advantage of the electronic control is the ability to accept more inputs about the system.

A mechanical system could use two wands (fore and aft) to get pitch and height, some dashpots to filter out the (chop) noise, etc. but it would be more complex to implement....but more fun for someone still a MechE.

KP

If anyone has an idea on integral control by mechanical linkage, let me know.

All I can think of is tanks filling up, there must be something more clever.

 

[atypicalguy]

Note BTW, while Clive has done something very cool, 5 hours of sailing time is rather minimal for sorting out durability and other issues. Remember that at a major regattae, you can crank out 5 hrs of sailing time in one day. And a control system that lasts but a week isn't going to cut it.

Note that while Wilbur and Orville have done something very cool, 26 seconds of flying time is rather minimal for sorting out durability and other issues...

If Clive's achievement were really so meager, surely you would have surpassed it by now...or are you holding out on us Baltic?

 

[BalticBandit]

Note that while Wilbur and Orville have done something very cool, 26 seconds of flying time is rather minimal for sorting out durability and other issues...
If Clive's achievement were really so meager, surely you would have surpassed it by now...or are you holding out on us Baltic?

Nope not at all. As I acknowledged in the other thread, I'm just an engineer who started as a MechE and then went on to electronics and software and am still in the process of saving pennies for a foiler.

I was primarily trying to forestall claims by HWMNBN that electronic controls are now a proven, race-ready technology. I fully expect that dramatic refinements can be achieved, but there's quite a bit of work ahead on proving it out. Meanwhile mechanical controls are race proven.

Where I could see electronic controls first making inroads is in the straightline Velocitek challenges where RRS and class regs on electronics don't apply.

 

[k_kirk]

I think there is room for wiggle here. The current rules read :

52 MANUAL POWER

A boat’s standing rigging, running rigging, spars and movable hull

appendages shall be adjusted and operated only by manual power.

hull appendages are defined here ( wont let me cut and paste) http://www.sailing.org/technical/ERS2005-2008.pdf page 12, but is basically anything that effects: stability, leeway, steerage, directional stability, motion damping, trim and displacement.

So in other words, unless you move your flap yourself you are in violation of the rules anyways. I am sure I'll get myself into hot water over this but I think all modern foiling moths using a wand to drive the flap are effectively in violation of the rule. So case in point, lets violate a little more and see what happens.

Personally I like the mechanical wand system and the issues that come with it. IMHO, mothing would not be as much fun if fly-by-wire was to take care of all stability issues and all we had to do was to be there. However, the geek in me wants to see this happen just for the sense of achievement.

My goal is to find a way to package an electronic solution for < USD500 and make it a plug & play add-on which can be installed over an existing standard Moth configuration with minimal modification. One can then sail legal in the competition and sail electronically assisted for a blast occasionally.

 

[the_skiff_devil]

We've already been through the rule 52 shenanigans when foils were first brought into mothing - the forward motion of the boat that moves the wand and drives the flap is interpreted as 'manual power' ie. it's not a stored energy device, so the existing mechanical wand devices clear the rule.

Electronics OTOH require stored energy of some description (unless it's run by solar or wind power and even then I suspect that the device would need to have no capacitance in the circuit as a capacitor is technically a means of storing energy...) and hence does violate R52. For that matter most of the modern canting keel maxis also violate R52 as they all use engine power to cant the keel... how do they get around it?

It's cool to see that someone's gotten out there and put into practice something that has been quietly talked about among the moth population for a little while; there was talk a while ago of simply using a wireless rotary detector attached to the wand in lieu of the existing mechanical rods and cables, with a small wireless servo installed in the head of the centreboard (and perhaps even the rudder), which would reduce the complexity of rigging a moth a little bit... make launching a matter of just plugging in the foils and going.

 

[clivee1]

To try and answer some of questions from both treads:

Thanks for all the positive comments.

I see what I have done as been very much the first step. Even on my boat there is a lot to be done to improve and refine the system. I have only just started.

At this stage I just want a cool boat that is fun and practical to sail and able join in races at a local club level. I do not have the time and no longer the inclination to put in the hours to compete in a formal class, and I get as much of a buzz from the development as the sailing. The restricted time means that my rate of ongoing development will not be that fast.

I do have ideas for the future to develop it for a foiling cruising tri, but that is many years away.

I think that many fast boats; foiling, multis and monohulls could be made to perform better with active pitch control.

If classes were to allow it I think that the cost would be similar to an auto helm product for obvious reasons. It need not be that expensive, however there are still people who choose to use self steering systems based on mechanical wands vanes levers etc.

I am not sure how the rules would stand if it was wind powered but this would be adding cost because of the rule.

I am not doing this as a commercial project. There are more effect ways to earn a living.

The electronics allows a more sophisticated and flexible control system to be implemented more rapidly than could be done with a mechanical system.

There are many ways to measure height. The wand is simple and cheap. You can also see what it is doing. At the moment I am getting occasional major wobbles whose origin is yet to be determined. If an IR or ultrasonic system were used it would take some development to be confident that its output was correct. Both have the ability to generate false readings in a number of ways. If anyone can point me in the direction of suitable devices I would certainly be interested but I see it as a very neat secondary development.

Do you know if the LED systems will reliably pick up a transparent water surface? The level of reflection could vary a lot.

Using accelerometers for height measurement is not practical. The measured vertical acceleration has to be compensated for changes in pitch and heel and these have to be separated from forward and some lateral acceleration. Small errors and offsets grow rapidly in the double integration to produce significant errors. I am trying to use a vertical accelerometer to work out whether inputs from the wand are due to chop/ motor boat wash etc or due to changes in height. At the moment I have not made the double integration stable over the few seconds that this needs.

Even if the electronics fully sorts the control of the flying it will not make these boats trivial to sail. They have no static stability they are very fast with a lot of sail and a lot of righting moment. At best they will still be as extreme to sail as any high performance dingy out there.

I agree with Ian Wards ideas from a few months ago that it would be great to see the Moth class get rid of many of its rules banning wig tip foils, multihulls, sailboards, electronics etc and see just how fast an 11’ dinghy could be.

If anyone else out there building 1 off foilers is interested in adding electronic control and sharing resources let me know.

Clive.

 

[k_kirk]

We've already been through the rule 52 shenanigans when foils were first brought into mothing - the forward motion of the boat that moves the wand and drives the flap is interpreted as 'manual power' ie. it's not a stored energy device, so the existing mechanical wand devices clear the rule.
Electronics OTOH require stored energy of some description (unless it's run by solar or wind power and even then I suspect that the device would need to have no capacitance in the circuit as a capacitor is technically a means of storing energy...) and hence does violate R52. For that matter most of the modern canting keel maxis also violate R52 as they all use engine power to cant the keel... how do they get around it?

The bungee chord stores energy but lets let it pass... Actually if you think about it even hoisting your sail up by pulling the halyard on any sailboat is a form of storing energy. Anyways. We all know our little voice will not change rule 52 so lets get on with it and experiment for the sake of "out of class" fun & development. Thanks for your input.

 

[k_kirk]

If anyone else out there building 1 off foilers is interested in adding electronic control and sharing resources let me know.

Clive, count me in. PM on the way for offline collaboration. Cheers & thanks

 

[Sailingkid]

We've already been through the rule 52 shenanigans when foils were first brought into mothing - the forward motion of the boat that moves the wand and drives the flap is interpreted as 'manual power' ie. it's not a stored energy device, so the existing mechanical wand devices clear the rule.
Electronics OTOH require stored energy of some description (unless it's run by solar or wind power and even then I suspect that the device would need to have no capacitance in the circuit as a capacitor is technically a means of storing energy...) and hence does violate R52. For that matter most of the modern canting keel maxis also violate R52 as they all use engine power to cant the keel... how do they get around it?

It's cool to see that someone's gotten out there and put into practice something that has been quietly talked about among the moth population for a little while; there was talk a while ago of simply using a wireless rotary detector attached to the wand in lieu of the existing mechanical rods and cables, with a small wireless servo installed in the head of the centreboard (and perhaps even the rudder), which would reduce the complexity of rigging a moth a little bit... make launching a matter of just plugging in the foils and going.

Couldn't you mount a little generator between the foils like the 747s have for when they lose power, because when your not moving your not going to need much electricity, and its not stored power because your using wind power to generate it, and your wont have to lugg one of those heavy batteries around. It would have to be dectachable so that you wouldn't need a massive trolley. Also you wouldn't be limited be battery life, in case you have to launch at like 8am, then get postponed for like 8 hours. See rendering.

 

[grooveman]

Couldn't you mount a little generator between the foils like the 747s have for when they lose power, because when your not moving your not going to need much electricity, and its not stored power because your using wind power to generate it, and your wont have to lugg one of those heavy batteries around. It would have to be dectachable so that you wouldn't need a massive trolley. Also you wouldn't be limited be battery life, in case you have to launch at like 8am, then get postponed for like 8 hours. See rendering.

Couldn't the moth foiler guys just wake up and make their own class rules? electronic control, bigger sail, slightly longer hull? why continue along the same limited rule path as the lowrider moths when you are so obviously in a different plane of design and performance?

 

[BalticBandit]

Do you know if the LED systems will reliably pick up a transparent water surface? The level of reflection could vary a lot.

depends on the tuning of the system. All air/water boundary layers reflect. What matters is the frequency selected and the gain in the system. I would think a bigger issue would be signal swamping from the sun. but clearly things like Laser rangefinders have solved this.

As for using a wand to measure height - don't you have some error caused by waves vs steady state?

 

[clivee1]

My next step is to use a vertical accelerometer to detect short term height changes and the wand to provide long term reference.

This is not as easy as it sounds. changes in pitch, heel forward and lateral acceleration affect the vertical acceleration reading. The double integration rapidly generates significant errors.

Will the LEDs be confused by water on the lens?

My preferred method of non contact height measurement is to look at the capacitance between an area on the bottom of the hull and the water.

Clive.