Software suggestions

[MarcusThatsMe]

TL;DR Summary

Need "affordable" software suggestions to allow me to build and simulate an experiment that focuses on weight, levers which gears would be moving along and raising a platform, counter weights.

I've been working on a problem for a while now, it's taken me into various directions, but I think I finally figured out the puzzle. But unfortunately I can't take it really any further, cost effectively, without some computer simulations of the experiment.

It's all basically physics based. I have a ramp that will be trigger to slope down, at which point a mechanism will move down the ramp while gears raise a platform with an object on it. Once it reaches the bottom another part of the system will remove the object and indicate that the ramp can return to its opposite position allowing the mechanism to move to the other side and reset itself.

I guess its a bit more complicated, but not in my head. I just need some soft of software that will allow me to build an environment and test the physics of everything.

Any thoughts?

And sorry if this doesn't belong in Mechanical Engineering forum, it sounded like the most logical location at the time.

Thanks!

 

[berkeman]

It sounds a bit like you want to simulate a potential Perpetual Motion Machine/Mechanism, but since discussions about PMMs are off limits at PF, we won't discuss that aspect.

What have you found so far in your Google searching for such simulation packages? What fidelity do you need in the simulation? In other words, do you just need something to keep track of positions and gross motions of things, or do you need to calculate forces and displacements with high accuracy?

 

[MarcusThatsMe]

It's not a perpetual motion machine, those are impossible. It's hard to explain, but trust me more energy is going into this thing then coming out of it.

Picture this. You have a cherry picker without an engine, as the wheels turn on its way down the ramp it lifts the cherry picker basket with a person in it using gears linked to those wheels.

I don't know if that is even possible, or if the cherry picker itself would require additional weight to force it down the ramp to force the cherry picker basket up. That's what I'm trying to figure out, that's my unknown.

It's not perpetual motion, it's just trying to figure out the force required? Maybe I don't need software for that, but I'm not sure how to calculate that and taking into account friction of the gears, etc. I figured software would be best for it.

Maybe that helps with the type of software as well, it doesn't need high accuracy, it just needs to give me an idea of its plausibility. Is it possible and what sort of additional energy is required if said energy comes from the weight.

 

[berkeman]

Picture this. You have a cherry picker without an engine, as the wheels turn on its way down the ramp it lifts the cherry picker basket with a person in it using gears linked to those wheels.

I don't know if that is even possible, or if the cherry picker itself would require additional weight to force it down the ramp to force the cherry picker basket up. That's what I'm trying to figure out, that's my unknown.

It's not perpetual motion, it's just trying to figure out the force required? Maybe I don't need software for that, but I'm not sure how to calculate that and the friction of the gears, etc. I figured software would be best for it.

You could start with a basic analysis of the Energy States to help you figure out if it should be possible. Do you already have Free Body Diagrams (FBDs) of the setup at the start and end of the travel/lift?

 

[Baluncore]

I don't know if that is even possible, or if the cherry picker itself would require additional weight to force it down the ramp to force the cherry picker basket up. That's what I'm trying to figure out, that's my unknown.

It seems, from your description, that the mechanism could be slowed down, yet still operate in the same way. You therefore need something that will model mass, position, and gravity, while conserving potential energy in the simulation.

 

[MarcusThatsMe]

You could start with a basic analysis of the Energy States to help you figure out if it should be possible. Do you already have Free Body Diagrams (FBDs) of the setup at the start and end of the travel/lift?

I don't, but I'll look into doing that next. Thanks!

It seems, from your description, that the mechanism could be slowed down, yet still operate in the same way. You therefore need something that will model mass, position, and gravity, while conserving potential energy in the simulation.

I'm hoping it can still operate the same way, despite the slow down. :)

I appreciate your input, I'll keep that in mind as I continue my search.

 

[berkeman]

I don't, but I'll look into doing that next. Thanks!

You're welcome, and I'm glad to hear it's not about PMMs.

For the energy calculation, calculate the overall gravitational potential energy (GPE) of all the parts of the mechanism in the initial position/configuration, and compare that to the end position/configuration to be sure that you are not trying to have the mechanism magically lift things against the force of gravity. As Baluncore says, this may require adding weight to the base vehicle, so it can elevate the weight of the cherry picker and its load in the bucket. Assume there is no motion (kinetic energy) at the start and end of the motion of the mechanism for the calculations.

 

[MarcusThatsMe]

You're welcome, and I'm glad to hear it's not about PMMs.

For the energy calculation, calculate the overall gravitational potential energy (GPE) of all the parts of the mechanism in the initial position/configuration, and compare that to the end position/configuration to be sure that you are not trying to have the mechanism magically lift things against the force of gravity. As Baluncore says, this may require adding weight to the base vehicle, so it can elevate the weight of the cherry picker and its load in the bucket. Assume there is no motion (kinetic energy) at the start and end of the motion of the mechanism for the calculations.

Forgive my non-technical nature, I'm diving into this because I'm excited lol

PE = mgh (mass * gravity * height) [for my reference to make sure I'm doing it right]

So for this could I just keep it simple, say the "body" (Wheels etc.), the "lift", and then the "basket" (if the object doesn't go above the basket).

Then I'd assume as you mentioned that I'd do that calculation based on what I know on all three parts once at the top in resting position then again at the bottom of the ramp at resting position.

I'll assume if the second number is greater then the first that I've messed with the universe and will need to make adjustments to compensate, such as those mentioned by Baluncore with adding weight.

 

[berkeman]

I'll assume if the second number is greater then the first that I've messed with the universe

Yes, that would be bad. Sort of like "Don't cross the streams!" "Okay, good safety tip."

PE = mgh (mass * gravity * height) [for my reference to make sure I'm doing it right]

So for this could I just keep it simple, say the "body" (Wheels etc.), the "lift", and then the "basket" (if the object doesn't go above the basket).

Yeah, something like that. Model the setup as the masses of things each located at their center of gravity (the vehicle, the two arms of the cherry picker, the cherry picker basket with its payload/person/whatever, etc.). Then draw the starting and ending configurations and their positions on the hill. The total GPE of the end configuration needs to be less than or equal to the starting GPE, and could only be equal if all of the bearing frictions everywhere in the vehicle and picker mechanism were zero. Make sense?

 

[DaveC426913]

Couldn't you just start with a sketch? As berkeman points out, a free body diagram would get you a long way, with much less effort and fewer false starts and rabbit holes.

 

[MarcusThatsMe]

Yes, that would be bad. Sort of like "Don't cross the streams!" "Okay, good safety tip."


Yeah, something like that. Model the setup as the masses of things each located at their center of gravity (the vehicle, the two arms of the cherry picker, the cherry picker basket with its payload/person/whatever, etc.). Then draw the starting and ending configurations and their positions on the hill. The total GPE of the end configuration needs to be less than or equal to the starting GPE, and could only be equal if all of the bearing frictions everywhere in the vehicle and picker mechanism were zero. Make sense?

I like the Ghostbuster reference

And excuse my mix up of words sometimes, I have dysgraphia, it can be a pain when trying to explain things.

It does make sense, it's a lot "easier" then I thought it would be. My only question is in regards to friction. In a perfect system there wouldn't be any friction, but that's basically impossible. Is there a safe way to account for that in the calculations using a hypothetical adjustment?

 

[MarcusThatsMe]

Couldn't you just start with a sketch? As berkeman points out, a free body diagram would get you a long way, with much less effort and fewer false starts and rabbit holes.

I'm starting to realize that, I'm glad I posted here, else I'd be making it SO much harder then it sounds like it needs to be.

 

[berkeman]

And excuse my mix up of words sometimes, I have dysgraphia, it can be a pain when trying to explain things.

Your writing is fine in this thread, to my highly trained eye.

My only question is in regards to friction. In a perfect system there wouldn't be any friction, but that's basically impossible. Is there a safe way to account for that in the calculations using a hypothetical adjustment?

So for the initial calculation, if you want to include friction I'd just say to use a 90% efficiency guess for now. So the total GPE of the final configuration should be no more than about 90% of the starting GPE. If your vehicle and picker bearings are worse than that in terms of friction or other losses, they should be replaced by better ones (if the efficiency is important).

After you get your initial idea of the numbers from the first calculation, that's when you can refine the calculation by including the dynamic stuff as the vehicle actually moves and lifts the picker mechanism. That's when you will want more accurate bearing friction numbers.

 

[MarcusThatsMe]

Your writing is fine in this thread, to my highly trained eye.


So for the initial calculation, if you want to include friction I'd just say to use a 90% efficiency guess for now. So the total GPE of the final configuration should be no more than about 90% of the starting GPE. If your vehicle and picker bearings are worse than that in terms of friction or other losses, they should be replace by better ones (if the efficiency is important).

After you get your initial idea of the numbers from the first calculation, that's when you can refine the calculation by including the dynamic stuff as the vehicle actually moves and lifts the picker mechanism. That's when you will want more accurate bearing friction numbers.

I had to go back and edit my messages real quick when I noticed something out of place ;)

No more than about 90% of the starting GPE, sounds good.

In order to get more accurate bearing friction numbers, I assume I'll have to graduate passed abstract boxes and actually build out the mechanism in some fashion. The night is young.

 

[berkeman]

In order to get more accurate bearing friction numbers, I assume I'll have to graduate passed abstract boxes and actually build out the mechanism in some fashion.

Not necessarily. If you are using standard mechanical stuff ordered out of catalogs or similar, the datasheets should include bearing friction numbers. The only subtlety then is converting bearing friction into torques, unless that is done for you in the datasheets.

I had to go back and edit my messages real quick when I noticed something out of place ;)

That never happens to me. Nope, ho no way.

 

[MarcusThatsMe]

Not necessarily. If you are using standard mechanical stuff ordered out of catalogs or similar, the datasheets should include bearing friction numbers. The only subtlety then is converting bearing friction into torques, unless that is done for you in the datasheets.

Brilliant, I wouldn't have thought of that.

Whats "cool" is I typed in the description of what I'm trying to do into CoPilot (AI), basically the same description here except instead of a human a 1 ton stone and it basically told me yes it's possible and this is what you do, which is crazy. It spit out a force calculation, mechanical advantage calculation and a safety factor calculation as well as suggesting to use a Rack and Pinion Gear System to convert the linear motion of the sled descending the incline into the lifting motion, which is of course the point we've been discussing.

I don't know, I'm a computer guy so the geek in me was curious.

Anyway, life got in the way last night, so I'm going to do the calculations suggested here today (roughly), then if it checks out like SkyNet thinks it should, I'll dive into starting to design the mechanism in order to get more accurate numbers of what the system can lift, etc.

Thanks again, this has been a very informative discussion!

 

[berkeman]

Glad that you're making good progress.

Whats "cool" is I typed in the description of what I'm trying to do into CoPilot (AI),

Please keep in mind that we do not currently allow AI as references in technical threads (it's still too inaccurate), so it's best to avoid mentioning that for now. Thanks.

 

[MarcusThatsMe]

Glad that you're making good progress.


Please keep in mind that we do not currently allow AI as references in technical threads (it's still too inaccurate), so it's best to avoid mentioning that for now. Thanks.

Roger that!