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« Last post by webby2 on Today at 12:19:44 am »
This is one of those things that has bothered me for as long as I can remember.
I come up with some mechanical idea, do a rough sketch and a very crude approximation of forces and distances and all that, build and test.
Now in the process of all this I get these force amplification relationships. In a lot of systems what I see, and can calculate, is a massive force being created but since it is against a non-changing part there is no work being performed and the very small reflected force that can move happens to match the input to the output for a 1:1 work value.
The part that bothers me is that I can build something to where that non-changing force goes to infinite, I can build this in the real world but of course things don't hold up to an infinite force but I can see these ridiculous force values trying to manifest. The bothersome part is HOW does the system only reflect the exact amount for a 1:1 work transfer? what is 0.1 percent of infinite?
I can't help but think that there is another level of communication that is happening between the input and output that I am missing, maybe we all are missing it.
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« Last post by webby2 on April 26, 2024, 10:40:49 am »
This is odd.
I can move the system with the same force on each side, if I start at the right non sticky spot that is.
I am not taking any notes on this but one way I can keep adding in more prime mover force while maintaining the same resistance force. This is not the same for all ways I can measure I think but the simple fact that I can do it at all is very odd.
Maybe it is just tweaking the frames and connection belt??? not sure.
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« Last post by webby2 on April 26, 2024, 03:55:05 am »
Getting a little confused.
I decided to add a pulley on the go-between part that rotates at a 1:1 with the input and output.
I measure that to the output and I get close to a 1:1 value, that is 1000g of pull on the prime mover needs about 900 to 950g on the resistance side, either direction of rotation.
I measure that to the input side and I get a much larger difference, that is close to 1200g for the prime mover needs about 900 to 950g on the resistance side, either direction of rotation.
I was getting a difference one way when measuring between the input and output, then I advanced the output and locked the output in place and now it is close to a 1:1 either direction.
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« Last post by webby2 on April 21, 2024, 06:59:27 pm »
0.017453292519943
(2*PI)/360
PI/180
so for 90mm arm and 360 degrees the distance is
((π÷180)×90)×360
565.486677646
or any degree you wish to use
((π÷180)×120)×360
753.982236862
In my system I do not need to worry about any of that stuff because I set all things, except those arm lengths, to 1:1. The input and output move the same distance, the force applied to the end of the arms moves the same distance,,,
In other words my belt needs to spin the identical pulleys so many times for the arms to make 1 complete revolution, it is not the length of the arms that counts.
I thought I only had to worry about 1 feedback loop that I easily took care of, however.
There is the lever relationship between the arms.
To simplify what I tested I will put it this way,
I applied a force into the connecting belt and measured the torque imparted into each arm without the rest of the system, so 10N of tension on the 90mm arm made 900Nmm of torque, 10N of tension applied to the 120mm arm made 1200Nmm of torque.
Then I started testing the steps, independent of the complete system looking for the other feedback loop that I missed.
I found the loop and it was not hiding at all I just missed it. The system is collapsing the distance of change into an internal change, or conversion. This feedback is between the go-between part and the output arm\pulley and it supplies a force of opposition to the change in position relative to the go-between parts that seems to mirror the change in distance of the arms, the output is 1.333 times the size of the input.
The force of opposition in my system then should look like 900g of pull on the input then goes across the system via the belt and drives the output arm to 1200g of force, then there is the internal force of opposition that reduces the available force down by 1\3 of 900 (the input force) or 300g of force leaving me with 900g of force on the output side.
The thing is that feedback oppositional thing is applied against the output and just like the spring between levers it does not matter which way the levers are moving that opposition is against the output arm. This then would infer that for me to take 900g of force from the input side I would need to supply the output side with 900g + the 300g for a total of 1200g of force.
Force must be supplied to both sides, that is how things work after all.
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« Last post by webby2 on April 21, 2024, 05:00:33 am »
if you have 2 levers and you use a spring to connect them together and you want to compress or stretch that spring you need to supply a force on each lever. While the spring is potentialized then it does not matter which way the levers move, that is one side moving up while the other moves down or vice-versa, the needed forces on the ends of the levers remains the same.
My system has 2 reactionary levers, the input side and the output side, the input is 90mm and the output is 120mm. These are locked into a 1:1 rotational value. I supply the input side with some force and that force is transferred via a belt across the system to the output side at a 1:1 so the output side sees the same force. All things, except for the reactionary lever arms, are 1:1.
It is my go-between parts that allows this to happen. What I thought was the only reactionary force I needed to counter was easy enough.
I was expecting that if I supplied the input side with a force potential so that the belt was transferring 10N of force that the reactionary arm of 90mm would create the appropriate work potential and that with the 10N of force being provided to the output side it would produce its appropriate work potential that was 1\3 more than the input side, being the arm is 1\3 longer.
What I got was close enough to a 1:1 pass through when the input side also supplied the motion to call it a 1:1.
When I measured the system when the output side was providing the motion things were different, I had to supply more force than I was getting from the input side. This is what I have been looking into.
I am slowly making parts to see if I am correct and to see if I can make a gain out of this, right now it does appear to be a sink, or a loss of work.
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« Last post by webby2 on April 19, 2024, 07:38:39 am »
strange,
The shift is not always the same, it is as if the tension in the belt is interacting with everything.
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« Last post by webby2 on April 19, 2024, 07:09:09 am »
Found an issue with the build.
2 pulleys printed from the same printer and the same file gave me 2 slightly different diameters. These are then walking around one another so that is what I think is showing the results I have been getting.
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« Last post by webby2 on April 13, 2024, 06:05:52 am »
trying all sorts of little changes and at this point the one thing I have noticed is that when using the 190g weights the system behaves a little differently than when I use more or less.
I add 30g to the output side and the nudge the system and it will slowly fall down a little bit, put it on the input side and I do not have to nudge the system at all. I have tried with my sync point moved, using CW and CCW rotation, switching the weights, so it seems that there is a preferred force direction of change, how much and why, not sure.
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« Last post by webby2 on April 13, 2024, 04:25:47 am »
I upped the weight to 270g and things appeared to become more "normal".
Then I thought about the limiter, so I shifted the system one way and not much change then I shifted it the other way and now the output side having the extra 30g goes up, very slowly and I need to nudge things so I am thinking that what I thought was "synced" may be in the wrong place.
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« Last post by webby2 on April 13, 2024, 04:07:49 am »
My setup needs some structural parts added but the functional parts are in place well enough for a few basic tests.
My spring scales are problematic in that I need to overload the system to get smooth readings and that drives the system out of sync so that a limiter I have in place comes into play and locks things. While it is in this condition if I pull on the output with 1200g I only need to supply 900g to the input, however if I pull on the input with 900g I only need to supply 1000g to 1050g on the output.
I changed up to dropping weights, each are 90g. When I reset so that the input and output are synced back up the input side has a very slight tendency to fall. I add another 30g to the output side and it has a small tendency to fall. If I give the system a spin it moves further one way more than the other, that is to say that the heavier side will continue to move down further than lifting it up. If I put the 30g on the input side it falls without needing to spin.
I increased the drop mass to 190g and the system seems to be balanced, no tendency to move either way. I add 30g to the output side and it drops fairly quickly, when I move the same 30g to the input side it drops very slowly and will stop moving until I give the system a little push.
Not the results I was hoping for, but not the results I was expecting. I was expecting the system to stay balanced and behave in a normal fashion.
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