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Force multiplier
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electrodacus:

--- Quote from: pcprogrammer on February 10, 2023, 12:29:03 pm ---Hear Hear  :clap:

My curiosity was triggered such that I decided to build my own vehicles to test the premises. Mind you it is just observational and not actual measurement to proof what is going on. I can't say much about the forces, because I do not have the equipment to measure them. And there in would lie the actual proof.

--- End quote ---

Glad to hear you where interested enough to decide and do your own experiments. Thanks.


--- Quote from: pcprogrammer on February 10, 2023, 12:29:03 pm ---But to me my experiment gave enough proof to believe that what Nominal Animal states is correct.

The attached picture shows the 3 vehicles I build. All have the same base structure, but different size sprockets.
The first one has a 1:1 ratio based on 20 teeth sprockets at both ends.
The second one has a 2:1 or 1:2 ratio (depending on how you look at it) based on a 10 teeth sprocket and a 20 teeth sprocket.
The third one has a 3:1 or 1:3 ratio based on a 10 teeth sprocket and a 30 teeth sprocket.

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The gear ratio makes no difference on how the vehicle performs.

For 1:1 there is no longer a define input as both size can be considered input or output so stored energy storage while charged has no way to discharge on just one of the sides thus vehicle can not have a net move in any direction as randomly one set of wheels will slip.
But it is still useful to show that the way belt/chain is connected makes this a locked gear and that is true for all other possible gear ratios.

Correct definitions are 2:1 and 3:1 since when looking at a gear box you need to know which one is input and which one is output and in this application the input is always the small sprocket. 1:2 will mean the large sprocket is the input and a gear ratio of 1/2 = 0.5 
While definition is not so relevant knowing what is the input on a system is important else you will think overunity is possible.


--- Quote from: pcprogrammer on February 10, 2023, 12:29:03 pm ---Using manual force on the frame with both set of wheels on the table surface it is easy to move the 1:1 ratio based vehicle, but basically impossible to move the other ones without slipping wheels or sprockets on the axles.

Using a piece of paper like shown in the video of IanB it is impossible to move the vehicle with the 1:1 ratio without either the wheels on the table to slip or the ones on the paper. In this case I call it just dragging things along.

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Of course that makes perfect sense because at 1:1 wheels rotate at same speed and forces are the same (no force multiplication)
When using any other gear ratio the wheels will want to spin at different rate and if they can not slip the vehicle is locked.
 


--- Quote from: pcprogrammer on February 10, 2023, 12:29:03 pm ---With the other two vehicles it shows the vehicle moving against the direction of the paper with different speeds between the wheels. This can easily be proven by the different distances traveled by the two axles. For this to work the wheels on the paper have the 10 teeth sprockets.

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Yes vehicle will move against the direction of input force / paper but the only reason that is possible is energy storage and stick slip hysteresis.
To verify this even with a high speed camera (it will be much easier with a camera at least 120fps if you have one to slow down the video).
But just try to move the paper super slow to see what happens and how force you apply to the paper needs to be so large that the wheels on the paper will need to slip before the vehicle can move powered by the stored energy against the direction of the paper. 



--- Quote from: pcprogrammer on February 10, 2023, 12:29:03 pm ---Reversing the vehicle such that the 20 teeth or the 30 teeth sprocket is on the paper, the movement reverses. The vehicle will start to move forward when the paper is dragged forward. There is again a difference in speed of the wheels, which is needed to make it work.

None of this shows any energy storage or slip stick hysteresis to me. With the bigger gear ratio the movement is very smooth.

All it needs is an initial force to overcome the friction and then movement starts. This force is supplied by my hand pushing or pulling the paper.

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Here is one of the other main problems and that is considering what is the input and output of the vehicle.
The fact that you put the large sprocket on the moving paper does not mean that vehicle is not the same so all you did was move the input on the table and output on the paper.
So the input in this case is the table and you need to look at the movement of the table surface relative to vehicle then see how vehicle moves relative to that.
You will also be able to see in slow motion that the first wheel that moves is the input so the one with 10 tooth sprocket on the table.

You have a more rigid belt/chain it has both flexibility and a bit of gravitational energy storage as the chain will be lifted when charged but the elastic is likely still the largest contributor.

That initial force is to make the wheel slide so is not about internal forces as it is about dragging the wheel until it slips.
If wheels are all equal the input wheel the one with small sprocket will always be the first to slip and if you can eliminate the slip at input wheel you will see that vehicle no longer moves against the direction of the input force but in the same direction as input force.

It is like saying that a incandescent lamp does not flicker because your brain can not see the fast changes in light intensity and so claiming that lamp works on DC instead of actual AC where light intensity fluctuates 100 or 120 times per second way to fast for our brain to notice.
My claims cannot be disproved with a fast motion of the vehicle and no way to slow down the video to see the charge discharge effect and stick slip hysteresis.
 

But anyone truly understanding Newton's 3'rd law will understand that an object can not move against the direction of the only force applied.
So please if you have a phone or camera that can do some god slow down video take the 2:1 vehicle and do some video in good lighting from the side so that the movement of the wheels can be seen. 
pcprogrammer:
I don't have a good camera to do this, and I don't need to be convinced about what is going on. I guess we have to involve the "slow mo guys" to make a proper video about it, but I don't think they will be interested in something like this.

But Nominal Animal was right, there is no convincing you. I just did the experiment to see for myself what happens and I have seen it with my own eyes and don't buy into the energy storage belloni you are trying to sell.

If you really want to proof you are correct, I challenge you to setup a verifiable experiment with measurement equipment and proof that way that there is happening what you claim there is. I don't have equipment for it so I can't do it myself.
electrodacus:

--- Quote from: Nominal Animal on February 10, 2023, 09:54:43 am ---It's not about internal friction, it is about traction in the wheels.  How about you actually try a 4:1 or higher gear ratio, instead of baseless assertions?

--- End quote ---

It will make no difference (as I mentioned I used 3:1) and had the same result. The higher the gear ratio the less the vehicle moves with every charge/discharge cycle. At some point is also possible for the belt connecting the wheels to slip wasting the stored energy.
According to your explanation F2 = F1 * 2:1 so F2 = 2*F1 thus why will you need more than this if it was true and at all times?

In reality F2=F1 that increases the F3 = F4 (belt energy storage) and only when input wheel slips the force form the energy stored in the belt adds to F2 and drops very fast as it is converted to vehicle kinetic energy then when it is used up the input wheel sticks again tho this time vehicle is in motion so stick slip happens much faster than first time as I showed in this graph except you can consider the time in ms (not sure what the graph was used for is from google search).

So unless you are superhuman you will not be able to observe stick slip hysteresis and energy storage without a slow moving vehicle and high speed camera.


--- Quote from: Nominal Animal on February 10, 2023, 09:54:43 am ---And I can show you the exact kinematics of why there are no such discharge cycles when the vehicle does not flex.  Yours flexes and behaves badly, because it has such a poor gear ratio, that's all.

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My vehicle is not flexing most of the storage is in the rubber belt but even if you make the rubber belt much stiffer all you do is increase the cycle of charge discharge with less energy for each cycle making it harder to see without even higher speed camera and at some point if you reduce the energy storage to much you need to increase the gear ratio significantly else will no longer work/move
Thus your need for larger and larger gear ratios as you reduce the amount of energy storage (elasticity of the elements involved).



--- Quote from: Nominal Animal on February 10, 2023, 09:54:43 am ---If you start your examination from the contact point between the driver wheel and the belt, you have four forces at that point, with the net result a clockwise torque on the axle (assuming belt surface moves left).  If we ignore friction losses in the gearbox, the gear ratio is also the torque ratio.  If your driver wheel turns twice for each driven wheel turn, then the torque at the driver wheel axis is twice the torque on the driven wheel axis.  (See e.g. here.)

The higher the ratio, not only is there more torque, but also the angular and thus linear velocity at which the driver wheel tries to move the vehicle is lower.  That is, with higher gear ratios (using your definition), there is more torque available to move the vehicle forwards.

With lower gear ratios, there is less torque available, and the velocity needed is higher.  When the gear ratio is insufficient, you will see jerkiness, because the wheels –– driven and/or driver –– will slip.  With higher gear ratios (or with wheels with better traction, or with heavier vehicle), there is less and less of wheel slippage, with sufficiently high gear ratios and/or heavy vehicles, the motion is absolutely smooth.

If you change the gearbox so that the driven and driver wheels turn in opposite directions, you just change the sign of \$\lambda\$ as described in my reply #97, noting that \$\lambda\$ is the inverse of the gear ratio as electrodacus prefers it to be defined.

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Can you please make a diagram and put the forces on that so we know what net force you are talking about ?
Also we may need to confirm what you consider the driver wheel ?
If this was a proper gearbox with 3 points of contact there will be no slip anywhere and smooth motion even when seen in a slow motion video and even with less than 2:1 gear ratio witch it is plenty and even with a 1:1 gear ratio.

It seems to me you start to admit that this vehicle can not move without wheel slip ?  If so I will consider this progress.


--- Quote from: Nominal Animal on February 10, 2023, 09:54:43 am ---So, you ignored my kinematics equations in reply #97, which shows that there are stable solutions for both same direction and opposite direction, whenever the gear ratio is outside the bad zone?

That with a straight belt, with treadmill surface moving left, the vehicle can move right at basically any speed except at the same speed that the treadmill surface moves left; but the vehicle can only move left faster than the treadmill surface?
That with a twisted belt, with treadmill surface moving left, the vehicle can move right only faster than the threadmill surface moves left; but left at basically any speed except at the same speed the treadmill surface is moving?

Everything I've told you and described to you is mathematically valid and verifiable in both theory and practice.  What you have done, is made assertions and shown one video that fails to perform as I've described, which you have taken as proof that no vehicle can perform as I've described.  Hell, I've even described exactly why your vehicle failed to perform, and instead of verifying it for yourself, you just assert that your vehicle is proof because you don't want to admit you're wrong here.

Are you sure you're not just playing word games and trolling here?  Are you here just to try and convince others that you are right, or are you willing to admit you're wrong and learn?

Testability is a primary aspect in science, and even more so in Physics.  You present one video of one non-performing device as proof, and ignore all examples of devices that are proven to perform.  You even assert that you don't need to modify your device, because the modifications do not matter!  In short, you are refusing to test your understanding.  That is not science, it is religion.

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No matter if belt is straight or twisted a vehicle/gearbox with only two points of contact can not do force multiplication. You need 3 points for a gearbox to be called a functional gearbox and be able to do force multiplication.
So the only configuration that will work with two points is twisted belt and 1:1 gear ratio none of the other vehicons can move without slip in the direction of applied force or stick slip hysteresis and energy storage in the opposite direction.

So if you want to prove my theory wrong you will need to show that your vehicle can move with no slip at any of the wheels. (not a little bit of slip or no visible slip but no slip).
If there was no slip allowed the belt or chain will be stretched until it breaks and nothing will move.
fourfathom:

--- Quote from: pcprogrammer on February 10, 2023, 05:01:14 pm --- I have seen it with my own eyes and don't buy into the energy storage belloni you are trying to sell.
--- End quote ---

What puzzles me is how this "energy storage" is even supposed to work.  If there is energy to be stored, then there is energy.  This energy can be accumulated and released in bursts (the stick-slip).  Sure, that can happen, we see it all the time.  But this energy can also be used in a continuous mode, without storage and release.  The amount of energy will be unchanged (ignoring losses in both cases), and stick-slip will not increase this energy.

Electronics analogy: PWM vs DC.

The models work with or without stick-slip.  Stick-slip does not increase the available energy.  Stick-slip is an irrelevant distraction.
PlainName:

--- Quote ---I showed in this graph except you can consider the time in ms (not sure what the graph was used for is from google search)
--- End quote ---

Hey, that's useful. Pick a random graph of something unknown on Google and then it proves whatever you want it to prove. If only other people knew that they could solve no end of problems!
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