Swiss Army Engineer: Web-based, Transient-First JVNcalc

This is a start to something… I wanted a JVN style calc sheet after seeing so many that didn’t do (everything) I wanted. Namely:

  1. Emphasize the use of transient analysis / simulation as the primary method
  2. Allow input of load equations, not just load numbers
  3. Work on any computer without need of an office package
  4. Maybe solve the over-proliferation of these things by using the power of git so we can merge things together :wink:

… And so rolling my own in vanilla javascript + google charting seemed to be a reasonable proposition.

Thusly, enjoy a first pass at such a tool: https://thaddeus-maximus.github.io/swissarmyengineer/

Go to the “Simple Mechanism”. This should encompass flywheels, drivetrains, arms, elevators… you name it!

If you have ideas and/or you want to implement them, github page is here: https://github.com/Thaddeus-Maximus/swissarmyengineer

There will be a lot more to come.

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But in all seriousness, cool!

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I might be missing something here, but curious - why does increasing the motor count decrease the time scale?

Also, this is gonna be annoying but… with JVN’s spreadsheet as the “trusted result” for some of these numbers, has any back-to-back testing been run to show the results align? I could totally go do this myself too, but curious if anyone’s tried yet.

But, well done overall! As beautiful as excel can be, an online version is a big step forward in ease-of-use IMO.

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The simulation (an Adams-Bradforth DE solver) is ran until either 1000 timesteps are made, or the end condition (which by default, isn’t filled in) is met. There’s also crude auto-time-stepping (using initial acceleration and max speed), so increasing number of motors decreases timestep. Basically… just fill in an end condition (say, t>2 or omega>2000) and this weird behavior goes away.

Any additional validation is good. I ran through and checked if the numbers lined up on a couple cases to be safe (on unit conversions and silly misplaced things), but the underlying physics is the same and rather well established.

Needs english units…

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