Author Topic: Active Pitchcontrol  (Read 331931 times)

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Steve Trumann

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Re: Active Pitchcontrol
« Reply #99 on: February 10, 2012, 09:12:13 PM »
I like it. That pitch control works a lot faster than I thought it would.
Steve Trumann




NoSmoke

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Re: Active Pitchcontrol
« Reply #100 on: February 15, 2012, 12:22:32 PM »
Hey Franz:

It's been quite a while since I have visited the Fieldlines forum and, perusing the various topics, I was especially interested to read the thread on your efforts with active pitch control.  As it turns out, I worked on a v similar project a few years ago, similar in fact to the point of using a Makita cordless drill (looks like the same model you used), threaded rod/nut, a push/pull rod through the main shaft and a "spider" mechanism to keep the blades synchronized.  I only proceeded however to a bench operational prototype (and crude compared to your device) but then came to the conclusion that I was not confident of building something sufficiently robust and reliable to put into actual operation - just too many potential failure modes I guess.

My project did differ from yours in that I utilized a micro-controller for the control function. It was the "PicAxe" type, a readily available, inexpensive and quite easy to program device (programmed in a type of Basic language).  Although my motor control was simply full on/off, forwards or backwards via an "H bridge", the processor is easily capable of servo and PWM so would IMO would be ideal for this type of application.  It would also offer good capability for things such as load control (MPPT?) and I'm now BTW working on a Picaxe based load control for my turbine.

Anyhow, I then turned attention to a passive type of pitch control using basically the same mechanicals as before but with fly weights attached to the blade shafts (with spring return) as the actuation mechanism (it's a 12 foot rotor BTW).  I use 1" ball bearing pillowblocks for the blade shafts (two per shaft) with 1 1/2"ers for the main shaft.  I have about a year now of cumulative operation and it has worked very well in all kinds of weather.  I especially like the ability to run even unloaded without problems and the fact it does not slow down or stop in strong winds like a furling system would (and of course it is inherently more reliable than an active system).

I've read comments here that pitch control mechanisms are problematical in that a lot of maintenance is required but I have found no particular issues.  I tend to build the stuff heavy (the pole top assembly is about 300 lbs total) and spray everything thoroughly with roller chain lube to avoid corrosion.  I have no weather enclosure on the pitch control hardware and was afraid the bearings might seize or corrode but have not found it to be a problem, at least so far.

I also thought about using bevel gears as you did for the blade syncing but was unable to find anything suitable at decent cost (I think that's the better way of doing it).  Would appreciate any ideas on a good NA source for such gears.

OK, enough for now but let me finish by saying what a great effort you have made, in both design and construction - certainly something to be proud of.

midwoud1

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Re: Active Pitchcontrol
« Reply #101 on: February 15, 2012, 01:55:10 PM »
Hey NoSmoke,

Glad to see you work with pitchcontrol , Active pitch is a lot of work because few people make it.
So you have to find out yourself.
I had to make several improvements to have something reliable .
The PIC-axe is an excellent controller to keep it on track. Here I have an LM2917 Frequency-voltage inverter as
an Rpm programmable switch. It is set on 330Rpm max.

 Bevel gears or (Tapered roller bearings) you can find it in the catalogues of SKF and Nachi etc. (32000 series.)
 I dont know your machines  Lathe and Mill . And that bearing should be made as a pillowblock.
 Aluminum block is good.
Only the inner blocks to hold centrifugal rotor forces.
Good luck .
 - F -

NoSmoke

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Re: Active Pitchcontrol
« Reply #102 on: February 15, 2012, 08:42:23 PM »
Frans, thanks for the bevel gear sourcing info.  That's a very nice looking control hub you have there but I wonder why both a spider and bevel gears are included (at least that's how it looks to me from the image).  Anyhow, that setup could be easily changed to passive (if active doesn't work out for you  ;)) by adding a fly weight and torsion spring to each shaft.

I don't myself have a lathe or mill - stick & mig welder, abrasive cutoff saw, bench & angle grinder and a drill press only so my construction capabilities are somewhat limited and, I buy a lot off-the-shelf as available (such as pillow block bearings).  I'm also pretty cheap so try the minimalist approach whenever practical.  One example is using cold rolled shafts instead of ground - I've found they make a surprising smooth & tight fit with the bearings and cost about 1/2 as much.

BTW, I've also experimented quite a bit with roller chain "gear ups" (driving a 3ph motor conversion).  This has also worked well.

fabricator

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Re: Active Pitchcontrol
« Reply #103 on: February 16, 2012, 07:15:56 PM »
The spider connects the gears, and keeps everything in sync.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

midwoud1

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Re: Active Pitchcontrol
« Reply #104 on: February 17, 2012, 03:13:06 AM »
Without the bevel gear there was a problem to move the blades synchronuously.
It would have caused flutter. I was lucky it was in the local transmission shop.
 

Menelaos

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Re: Active Pitchcontrol
« Reply #105 on: February 17, 2012, 12:16:15 PM »
Hey,

Ich well believe that withe the gear, the synchronisation is far better...but now it is some kind of double synchronisation, isn't it? What is the spider still useful for if the gear does the job now? Or did I miss something?

Max

bvan1941

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Re: Active Pitchcontrol
« Reply #106 on: February 17, 2012, 12:50:17 PM »
miwoud1,
Very nice project and I have followed your progress for some time. I know you've studied various connectivity variations and the blade drive combinations.
Question: In the interest of simplicity at driving(controlling) the blades, If the spider were to be replaced by another bevel gear(connected to a rod coming thru the hole in the sungear), wouldn't the mechanism moving the blades be simplified using the rotary motion, vice having the drills rotary motion changed to a linear in/out motion to move the spider (hence the blades)? 
Just asking, I'm certainly not criticising.
Bill

fabricator

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Re: Active Pitchcontrol
« Reply #107 on: February 17, 2012, 03:07:26 PM »
It could be even simpler than that, you only need one sun gear, the existing sun gear moves the pinions if it is driven.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

midwoud1

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Re: Active Pitchcontrol
« Reply #108 on: February 17, 2012, 03:48:41 PM »
Hi.
Moving the sun gear rotation left and right to change blade-angle.
Now we have two rotations  1) the mainshaft 2) the sungear independent
of the mainshaft  making 45 deg left and right.
Looks to me a bit more difficult.
The push-pull rod and spider will do good when more rigid, and free of slob .
That can do without bevel gear
The actuator with spindle is fine ( choice of speed ) and high torque.
Good to control with electronics.
In the near future with a microcontroller.

   - Frans -

fabricator

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Re: Active Pitchcontrol
« Reply #109 on: February 17, 2012, 06:03:56 PM »
Personally I think you are right.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

NoSmoke

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Re: Active Pitchcontrol
« Reply #110 on: February 17, 2012, 09:05:24 PM »
Frans, yes I can see the gears give good sync.  I too was concerned about flutter when I constructed my spider so I took care to make the linkages tight and low friction.  There may be a small amount of flutter but it is not apparent from the ground at least.

I also agree that the push-rod control with gears would give the best results over gear control alone.

I'm wondering, is there such a thing available as a suitable linear servo actuator (something to replace the drill & threaded rod)?

What type of micro-controller will you be using?

I'd like to try the gear method but those suckers aren't cheap - looks to me over $200 for four.  Maybe a transmission rebuild shop could supply some used ones(?).

midwoud1

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Re: Active Pitchcontrol
« Reply #111 on: February 18, 2012, 04:46:13 AM »
NoSmoke.  We can find 4 bevel gear wheels inside a car dif. on the scrap yard.
From the type of a Pickup truck cardan .
Think these are hardened steel so we must anneal to work on it.

A suitable lineair actuator can be found in our adjustable bed mattress.
Or the window opener servo in our car. ( Scrap yard )
On Mobile scooters that disabled people use.

The type of micro-controller , I still have to find out , need more info about it.
Think a PIC 16f877 will do , I have to learn about programming language
 ( Basic , JAL )

 - Frans -

NoSmoke

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Re: Active Pitchcontrol
« Reply #112 on: February 18, 2012, 05:21:51 PM »
Yes, the 3a, 3b, 9a & 9b gears ought to do it.  Does anyone know exactly what they are called so if I call an auto wrecker I will know what to ask for?  Would those four mesh together or would gear 10 also be required for the "centre" gear?

To anneal them would one just place them in a hot oven for a while?

RP

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Re: Active Pitchcontrol
« Reply #113 on: February 18, 2012, 06:35:29 PM »
"spider gears"

JW

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Re: Active Pitchcontrol
« Reply #114 on: February 18, 2012, 08:16:52 PM »


It looks like only one gear, but the other may have been removed for the picture- would be interesting to know if the bevel gear is gounded to the assy, or freely rotates, im sure backlash is a proplem with the design.

JW

NoSmoke

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Re: Active Pitchcontrol
« Reply #115 on: February 18, 2012, 08:27:39 PM »
Thanks RP.

JW, the sun gear has to float otherwise the blades could not rotate with respect to the assy. 

There might be a little backlash if the gears aren't tight but I doubt it would be noticeable.
« Last Edit: February 18, 2012, 08:30:10 PM by NoSmoke »

JW

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Re: Active Pitchcontrol
« Reply #116 on: February 18, 2012, 08:38:39 PM »
What concerns me is, its a single axle design. I understand planetary gear clusters. With 2 bevel gears, the assy would be much more solid. Could the common shaft for the bevel gears intesect, most likely yes.

This would attempt to nullify, the torque spread out on the surface area of each blade, into the gear cluster. I agree that backlash sread between both gears would be easier to control, overtime, and constant duration of use. It comes down to the surface area of the gear mesh being doubled, with 2 gears over one. I think only one gear as illustrated in the photo, is a bad idea. But thats only my opinion.

JW

rossw

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Re: Active Pitchcontrol
« Reply #117 on: February 19, 2012, 01:20:29 AM »
would be interesting to know if the bevel gear is gounded to the assy, or freely rotates, im sure backlash is a proplem with the design.

If the bevel gear was "grounded" (presume you mean firmly attached, unable to turn) - surely the other gears in mesh with it, couldn't turn then either?

RP

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Re: Active Pitchcontrol
« Reply #118 on: February 19, 2012, 10:24:48 AM »
Actually if you put a second bevel gear in front, it could be attached to the rear one by a bearing/bushing and shaft and the pair of them could "float" without being tied to the frame at all.

I don't see an advantage to doing that but it may allow some more choices or eliminate some headaches.

midwoud1

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Re: Active Pitchcontrol
« Reply #119 on: February 19, 2012, 10:42:09 AM »
Gentlemen . Dont worry about backlash. All the parts are machined precisely and adjustable . The bearing housings are very tight-fit ,that will never move out by centrifugal forces . There is an extra ring to hold against axial force.
The sun gearwheel is free running around a hollow POM shaft.
The blade-pitch is running light , you can move it with your finger tips.
If anything goes wrong I'll report it.
http://www.youtube.com/watch?v=RiQiqi5jzVs&list=UUhmCD9VGJTBJsh0tCDHsHbw&index=2&feature=plcp

 - F -

JW

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Re: Active Pitchcontrol
« Reply #120 on: February 19, 2012, 10:56:14 AM »
I want to say I think this an really good example of innovation. I like this machine...

Yes RP there is an existing bevel gear below, but not one on top, I think the arrangement with both bevel's would be simular in action of a open differential (link a car has).

The primary drive bevel gear will regulate the outer bevel gear using the blade gears. So it would effectively float(outer gear), and having a common shaft for the bevel (pinion) gears, would assist in eliminating wear on all the gears, depending how strong you want it to be you could use a thrust bearing(outer pinion gear shaft). The pinion's shaft would be in parallel to the turbine axle.

This an excellent project. And it will work fine the way it is.


JW

NoSmoke

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Re: Active Pitchcontrol
« Reply #121 on: February 19, 2012, 12:02:39 PM »
Frans, are all four gears alike (sun gear same as blade shaft gears)?

Has anyone actually bought these "spider" gears from an auto wrecker?  Do they typically sell them separately or would one have to buy the entire differential and disassemble it?
« Last Edit: February 19, 2012, 12:05:25 PM by NoSmoke »

fabricator

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Re: Active Pitchcontrol
« Reply #122 on: February 19, 2012, 12:16:53 PM »
You're gonna have to buy and likely remove the diff from the car, you want the large sun gear and the small planetaries, although you will only be using three of the small gears.
I would think finding something small enough would be problematic with auto parts, the smallest sun gear in an automotive application would likely be at least six inches in diameter.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

fabricator

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Re: Active Pitchcontrol
« Reply #123 on: February 19, 2012, 12:20:20 PM »
I want to say I think this an really good example of innovation. I like this machine...

Yes RP there is an existing bevel gear below, but not one on top, I think the arrangement with both bevel's would be simular in action of a open differential (link a car has).

The primary drive bevel gear will regulate the outer bevel gear using the blade gears. So it would effectively float(outer gear), and having a common shaft for the bevel (pinion) gears, would assist in eliminating wear on all the gears, depending how strong you want it to be you could use a thrust bearing(outer pinion gear shaft). The pinion's shaft would be in parallel to the turbine axle.

This an excellent project. And it will work fine the way it is.


JW

KISS, in this case is very appropriate on several levels.
I aint skeerd of nuthin.......Holy Crap! What was that!!!!!
11 Miles east of Lake Michigan, Ottawa County, Robinson township, (home of the defacto residential wind ban) Michigan, USA.

NoSmoke

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Re: Active Pitchcontrol
« Reply #124 on: February 19, 2012, 12:36:59 PM »
You're gonna have to buy and likely remove the diff from the car, you want the large sun gear and the small planetaries, although you will only be using three of the small gears.
I would think finding something small enough would be problematic with auto parts, the smallest sun gear in an automotive application would likely be at least six inches in diameter.

OK but I wonder if four planetaries would mesh (one as the sun gear)?  That's what it looks like in Frans' pics.

midwoud1

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Re: Active Pitchcontrol
« Reply #125 on: February 19, 2012, 01:29:40 PM »
It depends on the size of the planetaries  2 inch will do
Important is the sequence of working.
If I work with differential compoments I would reduce dia. partly of the blade shaft
equal to length of the planetary gear hole. Clean it with alcohol . Glue the components with Loctite HD . That will never walk away. Make a well locked retainer ( with a tension dowel, sorry I dont know the english word for it ).
Or 3 sinked centers in the shaft with high quality internal hex screws
On the retainer can the spider-linkage-arm be fixed.
After the retainer there is the inner blade shaft bearing.
The distance between the inner and outer bearing , I have 70 mm.
After the outer bearing another retainer with 2 normal hex. screws fixed.
Keep enough shaft length  for blade fixation.
Lay these component on the table with the sunwheel meshed in.
Now you can determine the radius and dia. of the rotor disc.
Make the height of the bladeshaft above the the disc, and the length of the linkage arm  , so you can move freely 45 degrees up and down from horizontal position.
Will be continued ,
- F -

JW

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Re: Active Pitchcontrol
« Reply #126 on: February 21, 2012, 08:51:17 AM »
I think this video Midwoud made is really cool... Great job!

http://www.youtube.com/watch?v=RiQiqi5jzVs


JW
« Last Edit: March 07, 2012, 09:04:20 AM by JW »

midwoud1

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Re: Active Pitchcontrol
« Reply #127 on: March 01, 2012, 05:15:05 AM »
Under construction
Blade pitchcontrol by a microcontroller they are available for a few euros.
And they have enough  analog and digital inputs to control Rpm .
In my case between 210 and 350. Programmable whatever you want.
Shutdown at windspeed 17 m/sec (signal anemometer )
Measuring Volt and Amps of the battery bank .
Stator temperature , vibration control ( ice one the blades )
Option with LCD readout display.

- Frans -

NoSmoke

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Re: Active Pitchcontrol
« Reply #128 on: March 01, 2012, 11:52:08 AM »
Frans, what micro and language are you using?

Any plans to do MPPT?

midwoud1

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Re: Active Pitchcontrol
« Reply #129 on: March 01, 2012, 02:26:42 PM »
Hi .

 Microcontroller  AVR-Atmel  or Arduino. Language  in C.
 Windpower compared with Battery demand and consumption with dumpload and         waterheater is the task of a controller.
First I concern on Rpm and MPPT later.

midwoud1

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Re: Active Pitchcontrol
« Reply #130 on: March 04, 2012, 04:51:58 AM »
Micro-controller.
I think the microcontroller can be a good assistant to control our windmills.
One of the ancestors is the organ you see playing at the canalstreets in Amsterdam where the lovely ladies also are.
Turning on a wheel and a perforated tape feed in and the whole orchestra is playing for you.
Another example is the teddy bear ,if you squeez his ear , or push on his belly he starts grumming or sing a song for you . I see students who hack that for another appliance.
There is even a book how to do that.
The controller can be used for run our mills safe and it costs only 20 dollars.
Connecting the hardware is a peace of cake.
Write a very simple program with your PC with your wishes and download it in the controller .
The program language is in - C -. Thats a bit complicated for a beginner.
Ask a friend software engineer to assist .
I think No-smoke can do that . Those programs can even be send by email .
We have the behaviour of the mill better in hand .
There are books on kid level to learn it.( Getting started with Arduino ) and we can find everything about it on internet.
A basic programme can be used for all of us .
We only have to feed in our data like Rpm , Bat.volt and Amps , Stator temp.
And Bob is your uncle.
I know that some people will say it's not KISS, But my laundry machine is working already 12 years with it.
- Frans -

NoSmoke

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Re: Active Pitchcontrol
« Reply #131 on: March 04, 2012, 02:51:29 PM »
Frans, that's a nice looking controller and I think I will take a look at them.  Still think however that a PicAxe & Basic would be easier for a beginner rather than C (not saying you are a beginner :)).  I've looked at C at bit and don't find it very easy or intuitive.

Anyhow, I would be v interested in updates to your project.  Maybe post some of the C code here?