LabVIEW simple pendulum simulation

[JÞB]

I'm curious,   was this a simple pendulum problem?  (Length and weight) a pendulum solved with correllis?  Or an inverted pendulum with a specific number of degrees of freedom?

Each is often called a pendulum problem.  I'm looking for some kind of scope to tag the replies. 

[gregTheEgg]

Hi,

there were no dimensional specifics, the tutor just wants to see us simulate SMH in Labview. It was a long time ago for me now but the uni are still using that same task because I usually get emails around this time of year asking me about it because of this thread. If you look at my original comment you can download the assignment brief, I'd be intrigued to see how others do it!

[altenbach]

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@gregTheEgg wrote:

there were no dimensional specifics, the tutor just wants to see us simulate SMH in Labview. 

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Well,, the dimensions (length, mass, damping coefficient, etc.) are inputs to the equations, so you just need to define them (via controls or diagram constants). Make sure to pick a combination that results in a reasonable simulation (e.g. not nanoseconds or years per oscillation :o). You also need to define an "interesting" initial condition (for example if you start at rest, nothing will ever move. 🙂 ).

I still recommend to implement all this using complex numbers. It will simplify things!:D

[JÞB]

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@altenbach wrote:

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@gregTheEgg wrote:

there were no dimensional specifics, the tutor just wants to see us simulate SMH in Labview. 

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Well,, the dimensions (length, mass, damping coefficient, etc.) are inputs to the equations, so you just need to define them (via controls or diagram constants). Make sure to pick a combination that results in a reasonable simulation (e.g. not nanoseconds or years per oscillation :o). You also need to define an "interesting" initial condition (for example if you start at rest, nothing will ever move. 🙂 ).

I still recommend to implement all this using complex numbers. It will simplify things!:D

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It is not often that I will disagree with Altebach.  Moving the problem into the complex plane in Cartesian coordinates does not simplify the problem as much as a transition to a Polar coordinate system.  Especially since rho (distance from origin) is lambda (pendulum center of gravity)  

Add a good offset to the dampening forces, such as a spring or weight, and you would have the basics of a clock.  

<Set Ancestry == TRUE> Bohrer's invented Cookoo Clocks in the Black Forrest. The Altenbach surname origination is within the general trade range.

[gregTheEgg]

I appreciate the input eveyone. Although, this is from the first module of a foundation course. Many of the students haven't heard of complex numbers and certainly most have not done any coding, labview or otherwise.

When I did it, what I was most keen to know was the rudimentary set up, do you link up a bunch of variables in a loop to make the equation and hook it up to a display or what? 

Even though this was long a go for me and I doubt I'll ever need to use Labview again, I would be interested to see how someone else does it

[JÞB]

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@gregTheEgg wrote:

I appreciate the input eveyone. Although, this is from the first module of a foundation course. Many of the students haven't heard of complex numbers and certainly most have not done any coding, labview or otherwise.

When I did it, what I was most keen to know was the rudimentary set up, do you link up a bunch of variables in a loop to make the equation and hook it up to a display or what? 

Even though this was long a go for me and I doubt I'll ever need to use Labview again, I would be interested to see how someone else does it

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What do they actually TEACH in school these days?  The most basic plane geometry course should have introduced the concept of complex numbers. And , by Gilgamesh, it took thousands of years for Descartes to introduce the X,Y concept and piss off all the Babylon mathematicians. 

Anyone claiming a free diploma from a high school that can't demonstrate that basic math MASTERY. should be considering an arts degree not a real degree.

[gregTheEgg]

Encouraging words there, thanks for your contribution.

Like I said, it's a foundation course. It's catered for people trying to get back into education who are expected to have the level of knowledge of a 16 year old.

Are you going to say anything helpful about how to use Labview, or just continue to be pompous?

[altenbach]

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@JÞB wrote:
It is not often that I will disagree with Altebach.  Moving the problem into the complex plane in Cartesian coordinates does not simplify the problem as much as a transition to a Polar coordinate system.  Especially since rho (distance from origin) is lambda (pendulum center of gravity)  .

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Complex data in LabVIEW can be handled as "RE/IM" or as "R/Theta", so you have your spherical coordinates right there! You can switch the view anytime according to whatever is most suitable for the current calculations without having to do any trigonometry (e.g. sin, cos, "inverse tan (2input)", etc.), greatly simplifying the code.

[JÞB]

The trig is inhierant to the coordinate change.

https://www.mathsisfun.com/polar-cartesian-coordinates.html

Angers Babylonians every time

[gregTheEgg]

I don't believe I asked about trig. I asked about how to use labview for the 5th time. And seeing as you're as patronising as you are unhelpful, you can go now.

Thanks altenbach for your clues!