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51
« Last post by webby2 on December 11, 2023, 07:21:20 am »
I can only run a static test, with that I setup where I thought the system should show a loss and it does show a loss but not as much as I thought it would be, so maybe the max loss part of the cycle is not where I think it should be.
52
« Last post by webby2 on December 11, 2023, 06:52:38 am »
I am running with only 1 set of 2 arms in this system and with what I have played with my expectations, if I were able to run a full cycle test, would be that the system would start at a net zero condition, ramp up to a maximum gain then down to a net zero then down to a maximum loss and back up to a net zero. I would expect that the maximum gain would match the maximum loss and show a complete cycle as a net zero.
If I were to add another set of 2 arms to the system then I would expect to be able to use the new set of arms as the transfer component instead of the loss cycle from the first set of arms, add more sets and I could be higher on the gain section. The more sets the higher on the gain slope the system could be maintained.
53
« Last post by webby2 on December 11, 2023, 05:33:31 am »
I got curious so I measured the force on the 8 rubber bands when pulled to the "starting" position length, that force was 7N
The hub piece has a 24mm radius.
I have 2 positions I can measure for an output.
The lock pin has a radius of 80mm and has a force at the "starting" position of 4N
The other pull point has a radius of 94mm and has a pull force at the "starting" position of 2.4N
My spring scale has 0.4N marks
Edit to add:
The "output" points and the input hub rotate at a 1:1 ratio
54
« Last post by webby2 on December 09, 2023, 08:22:02 am »
Still just playing around.
I have been looking at what kind of exchanges I can have and what makes sense and what does not,,
I thought of something last night and then after thinking about it it seemed like it would have to end up being a net zero, well I printed a few parts off overnight and thought I would just go ahead and play with them, then I found that I made one hole to big for the screws I am using, anyway I just used a nut and bole and locked those parts together instead of allowing them to move on a bearing.
So my gears haves a 24mm radius boss, so a pulley if you will, I used the teeth to hold onto 8 rubber bands and held the other side to a non moving part, then I used 1 rubber band on a part that has a 100mm radius, the 1 rubber band would stretch and then it would move everything and stretch out the 8 rubber bands.
Not sure if it means anything but I thought this usage would not do anything.
55
« Last post by webby2 on December 05, 2023, 05:45:22 am »
Not sure what this means.
While I am just playing and printing more parts for testing stuff.
I set things up in a strange almost backwards way, then I use Mr. Hand to hold the output still and then use the other Mr. Hand to apply force against the input arm. I then shift things so that it is close to where I think a force gain situation should be,,, now the funny thing happens. I move the arm and of course the output moves then I take Mr. Hand on the output and I increase the resistive force he is applying. Well, Mr. Hand on the arm does not feel that increase in force but several of the parts bend and flex more, as I would expect from the increase in force from the output.
56
« Last post by webby2 on December 04, 2023, 05:27:50 am »
This should not need to be said, but, no engineer would design one of my systems to work the way I am using it
57
« Last post by webby2 on December 04, 2023, 04:20:51 am »
I have a build error that I did not know about. I have 8 sub-systems with a part that connects to all of them and they all are supposed to be in sync with their motions and stuff, well somehow either a design error or a slicing error or a Freecad error, the systems are sort of indexed so that they all only line up when the parts are put together in one orientation and that still does not work nicely. The system is supposed to allow for a free rotation between all the parts but as the system rotates it starts to bind and that spring loads the actual parts so there are 4 positions that it wants to stop in. This is not a good thing for me.
This test-part was setup so that I could use it for testing 2 different thoughts on how to transfer the work.
One way would require that I flip the input and output functions at the appropriate time while maintaining a constant reactionary condition. I could see Bessler using something like this for his wheel since Gravity is directional it would provide a means to facilitate the flip and then he might be able to use the constant reactionary condition as his actual output.
Another way, which I am preferring to use, has a constant input and constant output and no flipping required. It needs a little better relational control and I think I should use a couple of limiters.
I have made my parts somewhat weak so that I can see the forces acting upon those parts, they bend and flex and it is this bending that I am using as a visual guide for the build. Obviously the final build parts will be stronger.
Another reason I chose to use 8 sub-systems is because each one can only pass a smallish amount of torque, 8 working together means I could pass 8 times as much before failure, hence the chain and sprockets to not only pass the output via the chain but the chain was supposed to keep all the parts in sync.
What I am seeing from my flawed test-bed, going for the constant setup, is that the forces and directions are doing what I was expecting. I have taken what should be an external rotation and stopped it and turned it into a virtual rotation.
I still need to design the feedback system that is needed between to parts, one moves a little relative and the other moves more, this work is the feedback I need to build for.
58
« Last post by webby2 on November 30, 2023, 03:50:31 am »
Throw away is not really correct but it kind of shares what I am not overly concerned with.
So, my test-bed allows me to transfer the work, via the perimeter of the wheels, through the system at a 1:1 rotation and a 1:1 force as seen by each wheel. I use the same size drive disc on each wheel and measure the same force and the same change in angle.
None of that should be a surprise since our math requires that this be the case as far as final values go.
I am mentioning this again because the perimeters are not the same and so there is a difference of distance traveled, this difference is made up for with the work transfer function of the designed interaction. This WTF is another exchange\conversion that happens internally, something I now have access to.
59
« Last post by webby2 on November 29, 2023, 04:55:23 am »
To be a little clearer, what I think I can do is throw away the change in distance so that my input force on the 100mm is the same force out on the 80mm,,, say 1N of force in and 1N of force out at a 1:1 rotation.
60
« Last post by webby2 on November 29, 2023, 04:45:45 am »
so my primary test-bed has proven many times and in different ways that my larger diameter wheel can drive a smaller diameter wheel at a 1:1 rotation and a 1:1 force for a 1:1 work transfer, it goes the other way as well.
This is all accomplished by some simple but maybe a little clever design where the hidden distance is allowed to exist. Think about this way, if I have a 100mm radius turning an 80mm radius I would need some kind of gear that has that 5:4 ratio, mine is a virtual gear but it is real enough to perform the function needed.
My new test-part is doing the same kind of thing but using a real gear instead and I am trying to design it so that it is a poor gear design, I am willing to throw away some work to losses.
I am shooting for basically a 100mm diameter turning an 80mm diameter at a 1:1 rotation and with a 1:1 force but minus those losses I am designing into the system.
I am going this rout since my chain and sprockets are not doing so well.
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