Thankyou Fletcher.
They say that practice makes perfect. You never know, maybe with a bit more practice i might just manage to get a simulation to actually rotate without the need for animated images.
Although i do think that is putting the bar a bit too high.
Gravity wheels with a fundamental difference
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Robinhood46
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re: Gravity wheels with a fundamental difference
Practice might not make you perfect. Apparently you need about 10,000 hours to become proficiently expert at anything worth doing in life. Like play the violin or play chess very well, tho who would want to ;7) You don't have to be perfect at it, just enough to bang out a kinematic sim in whatever program you are currently using.
First you build things as accurately as you can for one mech. Then you copy it as many times as you need to. And place them accurately etc. Watch on-line tutorials etc. That's a good start.
Then some truths come home to roost.
A kinematic sim will rotate (without the aid of a motor etc) when it is free to move, and not balanced. And it always does the same thing. If there is Net Torque in one direction (CW or CCW unbalance) then the wheel will rotate in that direction. BUT .. this cannot happen unless the whole structure can lose Gravitational Potential Energy (GPE). IOW's the system CoM must lose height in order to turn and give Kinetic Energy to the structures making up the wheel in its entirety. And if considering a frictionless environment as best case scenario then the Total KE can not exceed the Net CoM GPE loss, in Joules. Classical Physics I'm afraid - wrt conservative forces and CoE, and known mechanical applications, as it stands.
But if we like to see how the wheel might rotate thru 360 degrees and beyond we can apply a cheat. We add a motor or some such which introduces Torque artificially. We can also add a force vector etc to do the same thing. We can turn on and off these cheats and see if our wheel responds differently at different rpms etc. What we are always looking for is an initially sustained acceleration which suggests an Excess Net Torque from our clever mechanics. This is what a Mechanical Gravity Enabled Wheel needs to produce to be a True Mechanical Gravity PM Wheel, imo !
Best of luck and have some fun .. it gets easier and easier the more you do. Just like when I bought a Dremel and Multi-tool, for some jobs at home. I made items twice. The first to learn what the tools could and couldn't do. The second to be pretty and enjoy the result.
First you build things as accurately as you can for one mech. Then you copy it as many times as you need to. And place them accurately etc. Watch on-line tutorials etc. That's a good start.
Then some truths come home to roost.
A kinematic sim will rotate (without the aid of a motor etc) when it is free to move, and not balanced. And it always does the same thing. If there is Net Torque in one direction (CW or CCW unbalance) then the wheel will rotate in that direction. BUT .. this cannot happen unless the whole structure can lose Gravitational Potential Energy (GPE). IOW's the system CoM must lose height in order to turn and give Kinetic Energy to the structures making up the wheel in its entirety. And if considering a frictionless environment as best case scenario then the Total KE can not exceed the Net CoM GPE loss, in Joules. Classical Physics I'm afraid - wrt conservative forces and CoE, and known mechanical applications, as it stands.
But if we like to see how the wheel might rotate thru 360 degrees and beyond we can apply a cheat. We add a motor or some such which introduces Torque artificially. We can also add a force vector etc to do the same thing. We can turn on and off these cheats and see if our wheel responds differently at different rpms etc. What we are always looking for is an initially sustained acceleration which suggests an Excess Net Torque from our clever mechanics. This is what a Mechanical Gravity Enabled Wheel needs to produce to be a True Mechanical Gravity PM Wheel, imo !
Best of luck and have some fun .. it gets easier and easier the more you do. Just like when I bought a Dremel and Multi-tool, for some jobs at home. I made items twice. The first to learn what the tools could and couldn't do. The second to be pretty and enjoy the result.
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Robinhood46
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re: Gravity wheels with a fundamental difference
If this is true then i should be proficiently expert at building PM wheels that don't go round on their own.Apparently you need about 10,000 hours to become proficiently expert...
Although i'm not too sure that it fits into that category....at anything worth doing in life.
I wish i knew why my computer just freezes the program (Blender) and i need to close it, open it again, without any trace of previous modifications.
Blender is far more interesting to use than Algadoo. My youtube video from 9 august is totally doable with Blender, if only the bloody thing would work.
"Kinematic" is a new word for me. Google tells me there are lots of different "kinematic" simulators available. I haven't yet worked out the difference between 3D simulator and Kinematic simulator, so i'll just have to download one and see.
Can you suggest which one is the most appropriate for my needs, at my level?
re: Gravity wheels with a fundamental difference
My bad .. I tend to interchange the terms kinematic and dynamic simulators without thinking too much about it. Mainly that they are quite different from animations. Altho a dynamic sim (using forces to move objects of mass) can be made into an animation for posting/viewing purposes (I haven't done that as yet) tho ME is a whizz at it.
The upshot is that some sims like Solid Works Cosmos are 3D simulators. You can rotate things around thru the 3 axes (x,y,z). Others like Working Model 2 Dimensions (WM2D) are as the name suggests, 2D. Generally this is no hindrance, because you have to select which body's collide and, if not, they will pass thru each other (not interacting) as tho it were a 3D representation, only in 2D. I default setup to no collisions and turn on what I need to save time. Both programs are used in industry and commerce whilst others like Blender and Algodoo (successor to Phun) not so much IINM.
Many of us have used the free download versions to greater or lesser success and frustration levels.
I tried Algodoo and frankly hated it. But then I'd had some previous experience with WM. The upshot is to try entry level programs (probably free downloads) and persevere with them until the Law of Diminishing Returns kicks in. You can out grow them, tho that might seem miles away atm.
Then back read the posts on the discussion board (generally tech forum) about various users preferences and the common traps for young players (and solutions) that come along and can trip you up from time to time. Generally finger trouble, and not understanding the program parameters (perceived as bugs rather than true bugs). There are workarounds. This can get you thru a bottleneck quickly as you step up the rungs of the ladder as a user. A common one is a simulation that once given a little nudge keeps turning and not slowing down causing the user to think they have PM (no friction losses). Many bold claims have come from this. Another is a sim that accelerates for no apparent reason. Usually parts are not placed accurately that 'overlap'. This means the program tries to separate the objects to acceptable separation (spits them out), and this gives the sim excess energy seen as an acceleration (mysterious added energy). Accurate placement removes the problem.
A sim is not a substitute for knowing some Classical Physics. It supplements your knowledge and they compliment each other. You can use both to cross-check each other, and in fact MUST. Otherwise rubbish in rubbish out as Raj is fond of saying.
With a bit of diligence old versions (cracks) of programs can be found on-line. If you are serious about a better quality program and want the full tech support then either purchase it on-line or take a license, as has been discussed many times elsewhere. For example WM2D comes out in a student version, and also as Interactive Physics IINM. All considerably cheaper than the full blown program used in industry. Not to say that we aren't industrious, but maybe not grand master experienced ;7)
The upshot is that some sims like Solid Works Cosmos are 3D simulators. You can rotate things around thru the 3 axes (x,y,z). Others like Working Model 2 Dimensions (WM2D) are as the name suggests, 2D. Generally this is no hindrance, because you have to select which body's collide and, if not, they will pass thru each other (not interacting) as tho it were a 3D representation, only in 2D. I default setup to no collisions and turn on what I need to save time. Both programs are used in industry and commerce whilst others like Blender and Algodoo (successor to Phun) not so much IINM.
Many of us have used the free download versions to greater or lesser success and frustration levels.
I tried Algodoo and frankly hated it. But then I'd had some previous experience with WM. The upshot is to try entry level programs (probably free downloads) and persevere with them until the Law of Diminishing Returns kicks in. You can out grow them, tho that might seem miles away atm.
Then back read the posts on the discussion board (generally tech forum) about various users preferences and the common traps for young players (and solutions) that come along and can trip you up from time to time. Generally finger trouble, and not understanding the program parameters (perceived as bugs rather than true bugs). There are workarounds. This can get you thru a bottleneck quickly as you step up the rungs of the ladder as a user. A common one is a simulation that once given a little nudge keeps turning and not slowing down causing the user to think they have PM (no friction losses). Many bold claims have come from this. Another is a sim that accelerates for no apparent reason. Usually parts are not placed accurately that 'overlap'. This means the program tries to separate the objects to acceptable separation (spits them out), and this gives the sim excess energy seen as an acceleration (mysterious added energy). Accurate placement removes the problem.
A sim is not a substitute for knowing some Classical Physics. It supplements your knowledge and they compliment each other. You can use both to cross-check each other, and in fact MUST. Otherwise rubbish in rubbish out as Raj is fond of saying.
With a bit of diligence old versions (cracks) of programs can be found on-line. If you are serious about a better quality program and want the full tech support then either purchase it on-line or take a license, as has been discussed many times elsewhere. For example WM2D comes out in a student version, and also as Interactive Physics IINM. All considerably cheaper than the full blown program used in industry. Not to say that we aren't industrious, but maybe not grand master experienced ;7)
re: Gravity wheels with a fundamental difference
As a footnote .. I started using WM mainly about 15 years ago. I watched the tutorials and was knocking out rudimentary sims in hours. Had a friend give me some pointers. Quite sophisticated ones (pertaining to our quest for PM wheels) within days. I soon reached the level of my incompetence at that time. IOW's I didn't need or have any need for the finer nuances of the program so my skills plateaued out at where I was comfortable. Necessity driven.
I used it for many years, put it away for months and years, and got it out again when inspiration took me. The skills quickly come back with a little practice.
Members like Wubbly have taken it to a new level from my perspective. He builds scripts to automate the building and editing of his sims. Call me old fashioned but I just tweak an already built sim and save it under a different name. He has learned how to put it into an animation program and upload it to You Tube. All excellent stuff and I for one appreciate his efforts, as we all then get to see and enjoy his sims as he would see them running on his own computer. And he explains what we are seeing for those not familiar with sims, or maybe Classical Physics pertaining to Mechanics.
I should take the next steps but motivation isn't in me atm. It does me fine for what I ask of it, I guess until the need arises.
And I think that is what motivates someone in this quest to learn a sim - when the need is there and it is greater than the fear of the unknown or failure, imo.
I used it for many years, put it away for months and years, and got it out again when inspiration took me. The skills quickly come back with a little practice.
Members like Wubbly have taken it to a new level from my perspective. He builds scripts to automate the building and editing of his sims. Call me old fashioned but I just tweak an already built sim and save it under a different name. He has learned how to put it into an animation program and upload it to You Tube. All excellent stuff and I for one appreciate his efforts, as we all then get to see and enjoy his sims as he would see them running on his own computer. And he explains what we are seeing for those not familiar with sims, or maybe Classical Physics pertaining to Mechanics.
I should take the next steps but motivation isn't in me atm. It does me fine for what I ask of it, I guess until the need arises.
And I think that is what motivates someone in this quest to learn a sim - when the need is there and it is greater than the fear of the unknown or failure, imo.
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Robinhood46
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re: Gravity wheels with a fundamental difference
Now this i do like, i like it a lot.
The principal looks very good.
There are plenty of variables that need playing with, and the construction itself is not a straight forward task.
There are 6 pairs of weights, are 2 sets of 3 next to each other doable or is 3 sets of 2 needed? All 6 can't be done all together. The thicness of a wheel is the last of our worries.
I think i have exaggerated the path of the swing, it wasn't intentional, it is difficult to accurately evaluate the true path of the moving pair, the weight on the rising side is further from the swivel point than it's partner and the difference will depend on a couple of the variables that need playing with. If left to raise a few degrees higher the swinging will be faster, if left to swing when it wishes naturally, where exactly would it start to swing, and where to?
Is a greater number of holes or movable pegs (swivel points on the wheel) a way of making the construction easier?
How far from the center should the holes be?
Is there an advantage to curving the arms, or are curved arms only needed if a central axis is prasent.
Lots of questions still, but looking good.
https://www.youtube.com/watch?v=LF9ahFtN3Ok
The principal looks very good.
There are plenty of variables that need playing with, and the construction itself is not a straight forward task.
There are 6 pairs of weights, are 2 sets of 3 next to each other doable or is 3 sets of 2 needed? All 6 can't be done all together. The thicness of a wheel is the last of our worries.
I think i have exaggerated the path of the swing, it wasn't intentional, it is difficult to accurately evaluate the true path of the moving pair, the weight on the rising side is further from the swivel point than it's partner and the difference will depend on a couple of the variables that need playing with. If left to raise a few degrees higher the swinging will be faster, if left to swing when it wishes naturally, where exactly would it start to swing, and where to?
Is a greater number of holes or movable pegs (swivel points on the wheel) a way of making the construction easier?
How far from the center should the holes be?
Is there an advantage to curving the arms, or are curved arms only needed if a central axis is prasent.
Lots of questions still, but looking good.
https://www.youtube.com/watch?v=LF9ahFtN3Ok
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Robinhood46
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re: Gravity wheels with a fundamental difference
This one is curious.
The 3 blocks of 4 weights are unevenly spaced around the wheel. 12 weights for 16 swivel points can't be equally placed around the wheel.
With each of the last weights leapfogging to the front of each block they redistribute the spacings of the 3 blocks.
I haven't put the springs in (couldn't be bothered), i delayed the weights moving to the rim on the descending side, as though there was a spring close to the swivel being compressed. Once again an exageration, i think, with the lifting of the weights at 7 ish (wishfull thinking). There is a lot of leverage to compress the spring but i think it rises too high. Maybe it would manage to move a weight that distance, if triggered after a few more degrees of rotation. It could also be lifted at 6, but much less.
With all these swinging weights i've been trying, i was hoping to see a peacocks tail opening and closing, fat chance. Maybe peacocks had different tails in the early 17 hundreds?
https://www.youtube.com/watch?v=K1KeM8WcWbo
The 3 blocks of 4 weights are unevenly spaced around the wheel. 12 weights for 16 swivel points can't be equally placed around the wheel.
With each of the last weights leapfogging to the front of each block they redistribute the spacings of the 3 blocks.
I haven't put the springs in (couldn't be bothered), i delayed the weights moving to the rim on the descending side, as though there was a spring close to the swivel being compressed. Once again an exageration, i think, with the lifting of the weights at 7 ish (wishfull thinking). There is a lot of leverage to compress the spring but i think it rises too high. Maybe it would manage to move a weight that distance, if triggered after a few more degrees of rotation. It could also be lifted at 6, but much less.
With all these swinging weights i've been trying, i was hoping to see a peacocks tail opening and closing, fat chance. Maybe peacocks had different tails in the early 17 hundreds?
https://www.youtube.com/watch?v=K1KeM8WcWbo
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Robinhood46
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re: Gravity wheels with a fundamental difference
This one is a slight variation to the others.
The principal is the same, only this time the arms are fixed to specific sections of the wheel. The weights are passed from one arm to the next.
This method may be easier to construct?? (The arms being fixed and passing the weights not neccessarily this version).
When Bessler removed the weights to move the wheel from one stand to t'other, was this easily doable because by design they are continually being seperated from arms during rotation?
Something along these lines would most definitely be gouverned by the diameter of the wheel for it's power. There is very little play possible with the arm lengths.
Maybe by using an odd number of arms, it would be possible to have 1 weight going in at the same time as another going out?
The falling of the empty arms, both long and short, to be ready for next weight, could possibly be used to compress springs to encourage the swinging? They could certainly be used for a triggering mechanism.
https://www.youtube.com/watch?v=dVb-I9qhyz0
The principal is the same, only this time the arms are fixed to specific sections of the wheel. The weights are passed from one arm to the next.
This method may be easier to construct?? (The arms being fixed and passing the weights not neccessarily this version).
When Bessler removed the weights to move the wheel from one stand to t'other, was this easily doable because by design they are continually being seperated from arms during rotation?
Something along these lines would most definitely be gouverned by the diameter of the wheel for it's power. There is very little play possible with the arm lengths.
Maybe by using an odd number of arms, it would be possible to have 1 weight going in at the same time as another going out?
The falling of the empty arms, both long and short, to be ready for next weight, could possibly be used to compress springs to encourage the swinging? They could certainly be used for a triggering mechanism.
https://www.youtube.com/watch?v=dVb-I9qhyz0
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Robinhood46
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re: Gravity wheels with a fundamental difference
This one is a bit different and in a different way.
There are two groups of 4 small weights accentuating the swinging of the pair of big weights. The two groups are seperated by 45°, one group at the front of the wheel and the other behind.
There are many variables/options to explore.
https://www.youtube.com/watch?v=HdX16gtbT14
There are two groups of 4 small weights accentuating the swinging of the pair of big weights. The two groups are seperated by 45°, one group at the front of the wheel and the other behind.
There are many variables/options to explore.
https://www.youtube.com/watch?v=HdX16gtbT14
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Robinhood46
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re: Gravity wheels with a fundamental difference
Back to the drawing board.
I'm sure i'm not the only one, who was rather hoping John's wheel was going to be a runner. With a bit of luck maybe someone will improve it and make it a success.
This wheel is simple in principal.
The 2 photos show one "T" shaped structure at it's place on the wheel when it does 'it's thing". Every other movement of all the weights are the consequence of this one movement., because they are all interconnected.
The 5 "T" shaped structures, progress radially around the wheel during rotation.
This very simple movement causes a lot of swinging and dancing of all the weights.
https://www.youtube.com/watch?v=YOCB-kX ... e=youtu.be
I'm sure i'm not the only one, who was rather hoping John's wheel was going to be a runner. With a bit of luck maybe someone will improve it and make it a success.
This wheel is simple in principal.
The 2 photos show one "T" shaped structure at it's place on the wheel when it does 'it's thing". Every other movement of all the weights are the consequence of this one movement., because they are all interconnected.
The 5 "T" shaped structures, progress radially around the wheel during rotation.
This very simple movement causes a lot of swinging and dancing of all the weights.
https://www.youtube.com/watch?v=YOCB-kX ... e=youtu.be
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Robinhood46
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re: Gravity wheels with a fundamental difference
At last, i managed to do a real simulation.
It still doesn't bloody work though.
Algadoo's limitations force me to make simple things, way too complicated.
Adding additional mechanismes and creating unnecessary movements, sort of goes against the basic rules of PM seeking.
The photo shows a steel weight added, tight up against the axle. This is enough to make the wheel turn and everything function, as best as can be achieved with Algadoo.
The interestig thing is that when it looks as though it will stop, the weight swings out on the descending side, and it regains a bit of speed. It does this until the weight is at BDC.
Don't missinterpret the use of the word "speed", nothing happens very fast. I added a gold weight for the video, so as to show how crappy the mechanism is, when any speed is involved.
https://www.youtube.com/watch?v=FRXKrqkFFGg
It still doesn't bloody work though.
Algadoo's limitations force me to make simple things, way too complicated.
Adding additional mechanismes and creating unnecessary movements, sort of goes against the basic rules of PM seeking.
The photo shows a steel weight added, tight up against the axle. This is enough to make the wheel turn and everything function, as best as can be achieved with Algadoo.
The interestig thing is that when it looks as though it will stop, the weight swings out on the descending side, and it regains a bit of speed. It does this until the weight is at BDC.
Don't missinterpret the use of the word "speed", nothing happens very fast. I added a gold weight for the video, so as to show how crappy the mechanism is, when any speed is involved.
https://www.youtube.com/watch?v=FRXKrqkFFGg
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re: Gravity wheels with a fundamental difference
Wow .. you've made some real progress in sim building skills.
Just a suggestion for presentation. Sometimes I make one mech and connections etc a different colour so it gives a reference for the eye. I find it easier to watch that one mech set change shape and move about etc. Then I watch the sim again to get a feel for the whole thing and how they interact. For me it's just a visual thing.
Just a suggestion for presentation. Sometimes I make one mech and connections etc a different colour so it gives a reference for the eye. I find it easier to watch that one mech set change shape and move about etc. Then I watch the sim again to get a feel for the whole thing and how they interact. For me it's just a visual thing.
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Robinhood46
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re: Gravity wheels with a fundamental difference
That is a good point.
I tried to do that before, LOL. It didn't work with the animations, the highlighted arms and weights would just step back in the same section. it would have meant doing hundreds of frame shots to get a full circle.
So i gave that up as a bad idea.
I've managed to get the hang of screen shots, but i haven't got a clue how to record a video of the screen yet. The smart phone does the job but the quality is a lttle bit under the weather.
I'm hoping to get my pc sorted to use Blender, which is about 4 million times better than Algadoo.
Is it possible with wm2d to make the arms swap swivel points?
I tried to do that before, LOL. It didn't work with the animations, the highlighted arms and weights would just step back in the same section. it would have meant doing hundreds of frame shots to get a full circle.
So i gave that up as a bad idea.
I've managed to get the hang of screen shots, but i haven't got a clue how to record a video of the screen yet. The smart phone does the job but the quality is a lttle bit under the weather.
I'm hoping to get my pc sorted to use Blender, which is about 4 million times better than Algadoo.
Is it possible with wm2d to make the arms swap swivel points?
re: Gravity wheels with a fundamental difference
Not that I know how to do effectively.Is it possible with wm2d to make the arms swap swivel points?
I think you may mean like latches or catches, except one pin joint lets go and another suddenly acts (a handover).
It can be done in WM using massless rods, and/or rigid joints and pivot joints. But you have to build an Output showing where they are positionally, or by circular degrees etc. Then you build IF statements in 'Active When' that turn them on or off according to your IF statement. The most important thing if using rigid or pivot joints is to have the iterations accuracy setting on Variable. Rods will still work on Fixed iterations but joints will sometimes miss or explode the program because they try to turn on or off between iteration steps.
I don't know Algodoo or Blender so good luck. Find some tutorials or a discussion group for the users of the program and ask questions.
re: Gravity wheels with a fundamental difference
I use Blender a little. I haven't used it for physics though, as I believe Blender is primarily for animation. (I don't use the animation part of it either)
I use it for designing parts as a CAD program, and it has its limitations there too.
I use it for designing parts as a CAD program, and it has its limitations there too.