Tracked vehicle construction?

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Postby Elliot » Wed Dec 23, 2009 10:30 am

:D
Hey Carmatic, welcome to the discussion!

This will take me a while to digest.

But I am VERY interested in your ability to invent new solutions in the realm of gearing. You see, I have a "holy grail of gearing" problem in front of me, which I have still not solved. So prepare yourself to be recruited! :lol:

Continuously Variable Transmissions intended for bicycles... we have. NuVinci, by Fallbrook Technologies. 0.5 underdrive to 1.75 overdrive. I'm running two of them IN SERIES on one of my Kinetic Kontraptions.

To be continued.
:D
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Postby motskyroonmatick » Wed Dec 23, 2009 10:55 am

Wow Carmatic!

When you bring a vehicle to the playa-- I definitely want to check it out.

Now you have me thinking about making the pedal powered golf cart I am working on dual powered. --WIND--

BTW I recently drained the gear oil out of my club car transaxle replacing it with 5-30 motor oil to reduce oil drag. I noticed no improvement but hopefully in ways that are not measurable by feel there is an over all improvement.

Now on to looking for vertical axis turbine designs for inspiration. :)
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Postby Elliot » Wed Dec 23, 2009 11:18 am

:D
Image

My two NuVinci CVTs in series, for a total range of 1225 %.

To be continued.
:D
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Postby Elliot » Wed Dec 23, 2009 8:22 pm

:D
All right.
Carmatic, I think I got so far as to understand that you are trying to improve on what-I-seem-to-remember-we-called the Bob Durst steering system. The magenta gear on the left side would correspond to Bob's figure-8 chain -- reversing the direction of that side's motion.

I've been translating Norwegian all day. A weird dialect of Norwegian. Maybe my brain will be clearer tomorrow.

Would you be able to give us a simplified version of your concept?

I'm going to glance over what we discussed here three years ago.

Wow.
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Postby Tiahaar » Wed Dec 23, 2009 9:10 pm

Impressive transmission Carmatic! And welcome from me to the boards also! Yes I agree with Elliot, this looks like a novel way to get differential steering, that is varying the amount of power by some means that is diverted to each side of the drive wheels/tracks. Are you planning a vehicle build? Keep us posted here!

As a side, the former TerraKrawler is about to loose its tandem pedaller attachment (going to a new KSR project). I still think that it is a workable machine, just needs more horsepower...like say a donor 12horse riding mower engine? Heaven knows the 2080 chain could take the output!
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Postby carmatic » Thu Dec 24, 2009 4:28 am

hey guys, thanks for all the positive comments
Elliot wrote::D
Hey Carmatic, welcome to the discussion!

This will take me a while to digest.

But I am VERY interested in your ability to invent new solutions in the realm of gearing. You see, I have a "holy grail of gearing" problem in front of me, which I have still not solved. So prepare yourself to be recruited! :lol:

Continuously Variable Transmissions intended for bicycles... we have. NuVinci, by Fallbrook Technologies. 0.5 underdrive to 1.75 overdrive. I'm running two of them IN SERIES on one of my Kinetic Kontraptions.

To be continued.
:D

interesting, 0.5 to 1.75 gearing? c would then nominally have to be (0.5)/2 = 0.25, and d be (1.75 - 0.5)/2 = 0.6125 , to ensure that the wheels can turn both ways at equal rates... like the reason for c is to make the differential gear stop at the CVT's minimum ratio, and the reason for d is to provide half of the maximum output speed of the differential...
i guess choosing a ratio of 2 for the gears has the added advantage of simplifying the calculations, since differentials output the average of their inputs...

if the exact gear ratios arent available, i guess you'd round it up to get a forward bias... or you could add a greater amount of forward bias to it too, depending on what you want, if you increase c such that its possible to get both the concentric gears turning in the same direction, you'll have abit less friction from the planetary gears, but it willl essentially be like a form of overdrive , in the sense that your only likely to use it when there's almost no resistance on the pedals and your leg muscles cant move any faster...

also, you are running one CVT after another? arent you worried about torqueing out the one down the line?
motskyroonmatick wrote:Wow Carmatic!

When you bring a vehicle to the playa-- I definitely want to check it out.

Now you have me thinking about making the pedal powered golf cart I am working on dual powered. --WIND--

BTW I recently drained the gear oil out of my club car transaxle replacing it with 5-30 motor oil to reduce oil drag. I noticed no improvement but hopefully in ways that are not measurable by feel there is an over all improvement.

Now on to looking for vertical axis turbine designs for inspiration. :)

im glad that you took up the VAWT idea, i first saw it on youtube videos... they make pretty neat decoration too, the horizontal visibility of their surfaces mean that you can paint them to blend right in with the decorations.... that and their mechanical simplicity make them ideal for festivals

imho, there's different types of drag that i know of.... one is viscocity, which increases with speed, think putting your hand out of the window of a moving car... the other is thixotropy, which would probably apply more to greases, it gives way once you force your way through it, think gummy substances like dough...
at the speeds of human pedalling, different viscocities wouldnt matter too much, but different thixotropic values, which normally dont matter under engine power, becomes very apparent... its all under the study of rheology, something im not too fussed about...
Tiahaar wrote:Impressive transmission Carmatic! And welcome from me to the boards also! Yes I agree with Elliot, this looks like a novel way to get differential steering, that is varying the amount of power by some means that is diverted to each side of the drive wheels/tracks. Are you planning a vehicle build? Keep us posted here!

As a side, the former TerraKrawler is about to loose its tandem pedaller attachment (going to a new KSR project). I still think that it is a workable machine, just needs more horsepower...like say a donor 12horse riding mower engine? Heaven knows the 2080 chain could take the output!

unfortunately, im not in a position to do any building... i dont have the space, i dont have the tools, and even if i had, i dont have the skills to use them...
to think, all the infinite dexterity of human hands, and all we're doing most of the time is pushing levers, turning cranks, and pressing buttons...

technically, the power , as calculated by multiplying the torque and the rotation rate, is constant to both drive wheels all the time...
so, intinuitively , the harder it is to move, the slower the vehicle will do so...
but as ironic as it may seem, moving in an environment which usually calls for more rigorous pedalling, would instead mean more delicate controls on the CVT's, lest you stall yourself out or move in the opposite direction...

the chain has an operating envelope between snapping from the torque and tearing itself apart from the speed, i guess you should be allright as long as you keep it geared between these two extremes...

----------------------------------------------------------------------------------

the only real concern with my transmission is if the CVT's give out after the vehicle has taken you deep into the middle of nowhere... thats why i chose a ratio of 1 for the CVT input, any lower and the torque might cause it to slip and wear out, any higher and the excessive RPM would overheat it or something

-----------------------------------------------------------------------------------

and i really think that adding width to the tracked vehicles is a good idea, so i'll bring that point up again...

assuming that you have one track stopped, and the other track driving... the vehicle would turn in a circle, centered on the stopped track...
the cleats on the stopped track would experience pure sidways motion, with it getting more severe towards the front and rear ends...
the moving track would trace out the outer rim of the circle, and its cleats would also experience some degree of horizontal motion, but its not as great as those of the stopped track...

the further apart the tracks are, the closer to a straight line the moving track will travel in... this would reduce the sideways motions on its cleats, and there will be less friction... also you will have a greater leverage to overcome the friction of the stopped track from...the 2 factors add up, so a little added width would have a big effect...

but you shouldnt go easy on the reinforcements against the side loads, tho, since your vehicle will turn both ways, and whichever track is slower/stopped will have the greater/greatest side load respectively...
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Postby carmatic » Thu Dec 24, 2009 5:13 am

Elliot wrote::D
All right.
Carmatic, I think I got so far as to understand that you are trying to improve on what-I-seem-to-remember-we-called the Bob Durst steering system. The magenta gear on the left side would correspond to Bob's figure-8 chain -- reversing the direction of that side's motion.


this is not true, both sides of my transmission are symmetrical, they are mirror images of each other... what you see in the diagram is half of the transmission driving one side of the vehicle...
the reversing effect comes from the relative speeds between a directly driven gear and CVT-driven gear

and that is, in essence, the simplified version of the concept
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Postby Elliot » Thu Dec 24, 2009 7:33 am

:D
Thanks, Carmatic, I'll try again. But I may never grasp this.

As for the two CVTs in series, yes, our main concern is the force on the second one. Notice in the photo -- by the size of the output sprocket on the first unit -- that I have the second unit spinning quite fast -- high speed low torque. Even so, I have no doubt overloaded the second unit -- and maybe even the first one! But no problem so far, and the factory has given me to green light to slow the second unit down. In a sense, we are trying to break it.

The unit is engineered for tens of thousands of miles in normal bicycle service -- upright riding position and a large front chain ring. If we can get 40 miles out of it under our brutal conditions -- "bench pressing" the pedals in recumbent position with an overall gearing of two Gear Inches -- we'll all be happy!

But this brings us to the other engineering challenge I mentioned earlier. What I really need is a transmission with a range closer to 2000 (two thousand) percent, and light and cheap. I'm thinking chain gang. I have one now, four gears and plenty range, but I have to stop and remove one chain and install a different chain in order to change gears.

Gemini -- it's 6:30 AM. I ought to go back to bed!
:D
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Postby carmatic » Thu Dec 24, 2009 4:03 pm

Elliot wrote::D

But this brings us to the other engineering challenge I mentioned earlier. What I really need is a transmission with a range closer to 2000 (two thousand) percent, and light and cheap. I'm thinking chain gang. I have one now, four gears and plenty range, but I have to stop and remove one chain and install a different chain in order to change gears.

Gemini -- it's 6:30 AM. I ought to go back to bed!
:D


a counter rotating pair of concentric gears , with the movement of the planetary gears between them as output, can have geared neutral if the linear speed of the concentric gears are equal....
by geared neutral, i mean it can literally come to a standstill, and the smaller the difference between the speed of the concentric gears, the slower the output will be... i.e. the ratio can go up to infinity

Image
this is for you guys who want to use 1 CVT, and use your crank-turning transmission design... this set of gears will adapt your foot pedal power towards the crank, and you can steer by actuating the CVT
the CVT is the golden gear, the brown gear is a differential, all the light blue gears have the same number of teeth, and the long purple gears are helical gears, i've drawn the orientation of their teeth
in the case of the CVT being able to be geared from 0.5 to 1.75 , the ratio between the light blue gear and the larger, slightly more greenish gear (the input for the CVT) would be
(1.75 - 0.5)/2 + 0.5 = 1.125
as in, the middle setting on the CVT would cause the differential to stop turning , therefore the maximum and minimum setttings on the CVT would cause the vehicle to turn at equal rates... the helical gears should be enough torque to work the steering, so the ratio on the CVT is not for torque but for equalizing the speed at its side of the differential

the drawbacks to this is that you wont be able to go backwards, and you will need to clutch the forward drive to be able to pirouette (turn on the spot)... plus who knows how the resistance of the CVT changes with gearing, it is possible that the vehicle turns one way easier than the other

---------------------------------------------------------

Elliot wrote:Thanks, Carmatic, I'll try again. But I may never grasp this.


what part of the transmission do you not understand? i can point it out step by step

my understanding is that you use 2 CVT's in parallel in order to get a wide range of ratios, like very low ratios for travelling uphill on land, and a much higher ratio for pedalling on water, eventually reaching 'double overdrive' as you work your way up the momentum of the wheel... am i right?
i would guess that they make different classes of CVT's, for different applications and torque levels... if cost is not an issue, i think its a good idea if the second CVT is from a heaver class than the first...

also im guessing that you need the continuously variable ratios for when you are going from water to land, as the wheel gets more and more ground contact...
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Postby carmatic » Thu Dec 24, 2009 6:15 pm

::edited::
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Postby Elliot » Thu Dec 24, 2009 6:32 pm

:D
Again, I'll have to get back to your steering system later. Too many irons in the fire -- and not enough fire! :lol:

Just one correction on my own drive system, and this was no doubt just a typo on your part: my two CVTs are in series, not parallell. You describe their operation correctly. And yes, water-to-land transitions are the most difficult part of the sport! You sound like a natural for Kinetic Sculpture Racing!
NuVinci makes only one size, as of yet.
Cost is very much a factor. They gave me the first two, and they have promised one replacement, but after that I will have to start paying for them.
...........

Word is, Santa has take off from the North Pole. Unjonharley bagged one of the raindeer for dinner, so Mary Poppins is filling in.

Peace on Earth.

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Postby carmatic » Thu Dec 24, 2009 7:11 pm

oops , yeah, series... i blame the lack of sleep

and dont mind my last post, i also blame that on the lack of sleep... sigh i'm only human after all... cant have people spending all that time, energy and money putting together something just to find that it wont work
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repost

Postby carmatic » Thu Dec 24, 2009 7:38 pm

and oh, seeing that it's Xmas today ( +0800 GMT , yes i live very far away), here's a picture of a suspension system i've thought up, drawn with particularly Xmassy colours
Image
the blue things are levers, and the small orangey circles are pivot points on the chassis
this allows the geometry and ground clearance of the suspension to remain constant, independent of the load carried... it also allows for an arbitary number of bogeys, i've used 5 as an example , but with the only springs you need being between the end bogeys and the chassis... alternatively, the blue levers at the ends are equipped with torsion bars.... that means 4 springs, one at each corner of the vehicle, regardless of how many bogeys you have... this stops the setup from collapsing to one side, which was why i deleted my last post

the outermost bogies provide compliance against obstacles by travelling inwards , and the rest of the bogeys accomodate the articulation with a combination of longitudal and vertical movement, with the articulation passed along the levers and each bogey 'absorbs' a fraction of the articulation by moving diagonally, in turn passing a lesser articulation to the next bogey...
its a mess, but it should balance out when it physically exists... track tension would have to be accounted for, just like any tracked system with suspension

okay, i think i got it right this time... dont worry guys, christmas hasnt been cancelled...
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Postby theCryptofishist » Thu Dec 24, 2009 8:35 pm

ibdave wrote:My Head Hurts now...

Mine, too. I don't know why I open this thread.
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Postby TomServo » Fri Dec 25, 2009 8:18 am

Bobcat tracks are relatively smooth, but heavy. Been thinking up a tank design myself. Using hydraulic motors, so each track can run at different speeds, for turning. A company in England makes a 1/4 scale Tiger 1, and probably sells the track you want. If I ever get on a real comp, Ill post a link.
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Postby dragonfly Jafe » Fri Dec 25, 2009 11:31 am

A person powered tracked vehicle can work (BioTrak was a partial success).

If I had cut all the overhead superstructure for the turret and the turret (with flame system) it would have been 30-50% lighter. A bigger torque arm was needed for steering (or more gear inches) - my original design of a 3-person crank (with 4 hand-holds) would have been much better (abandoned due to time constraints). The biggest issue was not bringing certain key track suspension parts, which allowed the track to wander in turns resulting in de-tracking. A more vigorous track alignment system (rather than just relying on the road wheels) would have helped.

I still have all the parts - BioTrak may yet roam the Playa!
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Postby TomServo » Fri Dec 25, 2009 12:00 pm

dragonfly Jafe wrote:A person powered tracked vehicle can work (BioTrak was a partial success).

If I had cut all the overhead superstructure for the turret and the turret (with flame system) it would have been 30-50% lighter. A bigger torque arm was needed for steering (or more gear inches) - my original design of a 3-person crank (with 4 hand-holds) would have been much better (abandoned due to time constraints). The biggest issue was not bringing certain key track suspension parts, which allowed the track to wander in turns resulting in de-tracking. A more vigorous track alignment system (rather than just relying on the road wheels) would have helped.

I still have all the parts - BioTrak may yet roam the Playa!


I've thought about pedal pwered tracks. Can you gear each track? A skid steer would seem a bit much for such little horsepower.
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Postby carmatic » Fri Dec 25, 2009 4:40 pm

TomServo wrote:
I've thought about pedal pwered tracks. Can you gear each track? A skid steer would seem a bit much for such little horsepower.


you can gear any rotating mechanism... you will get smoother steering with CVT's, tho

steering can be made easier if your vehicle is wider
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Postby Oldguy » Sat Dec 26, 2009 1:18 am

I remember driving a M113 armored personell carrier in the army, where each track not only had its own accelerator but its own brake. We could also stop the machine, put one track in reverse: and then accelerate in a spin in the same spot. A nice tactic if you didn't want to be shot in the ass, where the personell door was. The crew could bail out the top from their own hatches, and passengers out the door.

We could steer while moving forward by speeding up one track or braking the other, or use a combination of both speeding and braking. We could also put up a lot of dust similar in effect to smoke, in dry soil.

Perhaps separate gearing and braking for each track might be possible in a chain driven vehicle. Or use pinion(?) gears and solid drive shafts like the old BMW desert rat bikes. Just brain storming here... Ever see a paddle boat with separate pedals for each side with a lever to switch to one rower or two? Think tracks instead of two paddle wheels.
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Postby carmatic » Sat Dec 26, 2009 4:00 am

Oldguy wrote:I remember driving a M113 armored personell carrier in the army, where each track not only had its own accelerator but its own brake. We could also stop the machine, put one track in reverse: and then accelerate in a spin in the same spot. A nice tactic if you didn't want to be shot in the ass, where the personell door was. The crew could bail out the top from their own hatches, and passengers out the door.

We could steer while moving forward by speeding up one track or braking the other, or use a combination of both speeding and braking. We could also put up a lot of dust similar in effect to smoke, in dry soil.

Perhaps separate gearing and braking for each track might be possible in a chain driven vehicle. Or use pinion(?) gears and solid drive shafts like the old BMW desert rat bikes. Just brain storming here... Ever see a paddle boat with separate pedals for each side with a lever to switch to one rower or two? Think tracks instead of two paddle wheels.


i also agree with having each track be independently geared

ideally, the gearing for both the tracks can be powered by a single source, the reasoning being that , rather than requiring a minimum of 2 people , and having the need to coordinate their pedalling speeds, only a single person is needed and the steering is done mechanically and intuinitively
so, in such a design, there will be a pair of almost seperate gearboxes , one for each side, sharing only the gears which receive motion from the pedals
using a lever switch to switch the drive between the sides is alot simpler, and alot cheaper and easier to build, since it would involve clutching and maybe braking one side, and diverting all power to drive the other side...

but i think that you can get smoother control and more efficient use of your energy by having abit more complexity ...
after all, in a tracked vehicle, you would be spending most of your energy overcoming the rolling resistance, not building up momentum...
the conditions you are operating in, and the resistance to movement, would vary alot, especially if you are trying to turn, but you can only pedal so hard... that is why i think CVT's are a good idea... not only do they let you precisely control your steering because they actually act like steering and not a gearbox with discrete gear changes, but you can also vary your speed as easily as you can steer...
and since you are gearing down rather than braking, all your effort is going into making the vehicle move, and it will always move, however slowly...


here's another diagram from me, lovely isnt it?
Image
using these definitions:
Wikipedia wrote:Sun: The central gear
Planet carrier: Holds one or more peripheral planet gears, of the same size, meshed with the sun gear
Annulus: An outer ring with inward-facing teeth that mesh with the planet gear or gears

this would be called Epicyclic Gearing

if the Sun gear and the Annulus gear spin in opposite directions, it is possible for the Planet Carrier to remain stationary...
but if either the Sun or Annulus speeds up/slows down , there will be rotation on the Planet Carrier...
and by speeding up/slowing down either the Sun or the Annulus just a little, there will be very little rotation of the Planet Carrier, this corresponds to a very high torque multiplication , and so the Planet Carrier is used to drive the wheels
the speed of the wheel being driven is controlled, in my transmission, by keeping the Sun gear spinning at a constant speed (or at least a speed directly proportional to your pedalling) , and gearing the Annulus through the CVT ... gearing the Annulus to turn faster would turn the driven wheel one way, gearing it slower would turn the driven wheel the other way
so, it is possible to go backwards and turn on the spot...

provisions can be made to compensate for the friction of the Planet gears, or the drag of the lubricant ... this is when the Annulus is spinning at its slowest, hence the Planet gears will also be spinning at their slowest speed, hence the friction will be the least... the direction that the driven wheel will rotate as a result , intinuitively, should therefore be the most common direction of rotation, i.e. forwards ...
so the higher the gearing of the CVT, the 'more backwards' you go, and the more friction from the Planet gears... but it is also possible to reduce this drag even more when travelling forwards, by having the Annulus and the Sun rotate in the same direction, resulting in a higher gearing for when you are travelling at high speed, in a straight line, on a smooth surface ... this is dealt with in my original posting, with the parameter c and the differential gear


any gear which is the smaller of the two is indeed called a pinion gear, the larger is called the 'wheel' ... that is according to Wikipedia, but in my experience lots of people call them different things...
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Postby TomServo » Sat Dec 26, 2009 5:04 am

Why did they make tanks so difficult? You for hire, when I hit the lotto?
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Postby carmatic » Sat Dec 26, 2009 5:58 am

TomServo wrote:Why did they make tanks so difficult? You for hire, when I hit the lotto?


as i understand it, Oldguy drove an armoured personnel carrier, not a tank.. but maybe the skills are transferrable?

also, real tank transmissions are far more complex than what i've brought up here... fluid coupling, stage after stage of reduction, hydraulics, automatic transmission, brakes... i believe that my transmission is the simplest way you can have a full range of motion, by utilizing CVT's


anyway, this is the full view of my diagram, where you can see both sides of the transmission
Image

compare this with a real tank transmission:
Image
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Postby TomServo » Sat Dec 26, 2009 6:21 am

carmatic wrote:
TomServo wrote:Why did they make tanks so difficult? You for hire, when I hit the lotto?


as i understand it, Oldguy drove an armoured personnel carrier, not a tank.. but maybe the skills are transferrable?


With a revolving turret, its a tank. Armored Personell Vehicle is almost the same. Same propulsion. Tank is just a prettier name. Artistry in excess
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Postby carmatic » Sat Dec 26, 2009 6:36 am

TomServo wrote:With a revolving turret, its a tank. Armored Personell Vehicle is almost the same. Same propulsion. Tank is just a prettier name. Artistry in excess


the thing is, just like a license to drive a car isnt a license to drive an 18 wheeler, a tank might require different training than an APC... the devil is in the details, see... the control layout might be different, there are different things you can and cant do, different procedures an equivalent manuever ...
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Postby dragonfly Jafe » Sat Dec 26, 2009 10:37 am

carmatic wrote:...steering can be made easier if your vehicle is wider


...ideally square for tracked steering - with my track rocker I was pretty close. And it almost spun in place (more torque and it would have).

I considered skid steering, but with the meager HP of 1-2 people pedaling, judged it to be too inefficient for my purposes (although the mechanisms to do the "Durst" style differential steering probably added 100 lbs vs. a few pounds for brakes to skid steer). For me, that is the essence of these projects - the design choices we make and the background research to get there)
Talent hits a target no one else can hit; Genius hits a target no one else can see.
Arthur Schopenhauer
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Postby carmatic » Sat Dec 26, 2009 9:44 pm

the added weight would not matter if you could gear down infinitely... this would be something like NASA's space shuttle transporter, 2mph unloaded, 1mph carrying its load .... slow, but gets the job done... as long as you have enough power to overcome the internal resistance of the transmission , which is a worry for my design since it involves constantly spinning spider and planet gears...

i think you really only have 2 choices... lighten up, or gear down ... for a tracked vehicle on a flat surface like the playa, its really limited by how well you can turn... but you can help it by having cleats with a rounded outer surface , so that the corners dont dig into the ground

also , sourcing the gears would be a big part of the research, the more exotic the transmission, the more exotic the gears... i dread to think how hard i have to look for an epicyclic gearing that functions like in my diagram, with the planet carrier acting as the final drive... or the gears which are driven with chains...
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Postby TomServo » Sat Dec 26, 2009 10:41 pm

carmatic wrote:
TomServo wrote:With a revolving turret, its a tank. Armored Personell Vehicle is almost the same. Same propulsion. Tank is just a prettier name. Artistry in excess


the thing is, just like a license to drive a car isnt a license to drive an 18 wheeler, a tank might require different training than an APC... the devil is in the details, see... the control layout might be different, there are different things you can and cant do, different procedures an equivalent manuever ...


I understand, I drive 18 wheeler combos. And as far as I know, each tank is different. Tiger tanks are much easier to drive, than centurions. I don't pretend to totallly understand each vehicle, but a do know their classifications. I LOVE tanks! I want to see this project on the playa. Carry on...
anything worth doing..is worth overdoing

Vor Gebrauch Sprengkapsel einsetzen
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Postby carmatic » Sun Dec 27, 2009 10:31 am

seeing Elliot's chain-on-chain CVT setup, it made me think that its possible to greatly simplify the transmission while still providing the full range of maneuverability and the 'geared neutral' ability

Image

the colour scheme is still the same... cyan are the input gears and gears which spin at the same rate, yellow is the CVT .... the medium horizontal lines are gear axles, the thick vertical lines are chains... the crossover in the middle is just that, a figure 8 chain to reverse the direction


in this transmission, there should be no gearbox to speak of, all you need to do is support or house the epicyclic gearset... it would be on the same axis as the driven wheels, and the Planet Carrier will be the final drive
the size of the Annulus and the Planet gears wouldnt matter , since the calculations are based on linear speed, not rotation rate... i.e. the linear speed of the Planet Carrier is the average of the linear speeds of the Sun and Annulus ...
and the linear speed of the Annulus is equal to the output of the CVT since it is connected by a chain... so all that's left is the rate of rotation of the counter-rotating cyan/Sun gear , multiplied by the number of teeth on the Sun to get its linear speed...
the gearing on the CVT's correspond to the gearing of the vehicle, and the smaller the Sun gear, the 'less reverse' you will have, which is the opposite of my previous transmission...
as it is in the diagram, with the Sun Gear having the same number of teeth as the cyan input gears, and with the CVT ratio going from 0.5 to 1.75, you will be able to travel forwards 1.5x faster than you can travel backwards


you will notice that my transmission, with the chain up the middle and opposing epicyclic gears, bears a resemblance to the Torotrak 'Infinitely Variable Transmission' ... but it is not the same, Torotrak's chain and Sun gear are geared through their CVT, while mine are driven directly... their Annulus is used as the output, while i use the Planet Carrier as the output... theirs run under engine power with a focus on overdrive for fuel-economic cruising, mine is specifically meant for gear reduction on low power...

but Elliot might be interested in their clutching mechanism, where the CVT drives the epicyclic gearset at low gear, then drives the wheel directly at high gear... with a gear sliding between 2 other gears, its doable with one NuVinci , the epicyclic would give you infinite torque, while the gear shift would give you water mode, at the shift point the meshing gears would be spinning at the same rate so its gonna be smooth

anyway, since it is all chain-based, the gears can be located independent of each other, much easier to plan into a vehicle, especially the location of the CVT's and how to actuate them...


the only problem remains finding the main ingredients of the transmission : a Planet Carrier outdrive, and gears driven with chains...
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Postby ibdave » Sun Dec 27, 2009 12:05 pm

theCryptofishist wrote:
ibdave wrote:My Head Hurts now...

Mine, too. I don't know why I open this thread.


Still husts...

I open only to have my hopes dashed.. I thought all thread were to have bOObies in them... Yes??


even if it's a bluefooted bOObie bird.... :shock: :shock: :wink:
I was Born OK the 1st Time....

Don't bring defaultia to Burning Man, take Burning Man to defaultia...... graidawg
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Postby pinemom » Sun Dec 27, 2009 12:58 pm

theCryptofishist wrote:
ibdave wrote:My Head Hurts now...

Mine, too. I don't know why I open this thread.





whoopsie....me either?
Names pinemom, but my friends call me "Piney".
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