With kickoff quickly approaching, I feel this is a good time to share the updated version of my design calculator spreadsheet. It features calculations that are very helpful for designing the mechanical, electrical, and pneumatic aspects of your robot.
The most recent version is posted below.
Please note that you need to enable macros for the Sprint Distance Calculator to work.
Changes since the last version:
Added Pneumatics Calculator, which allows you to predict air volume usage based onthe number and size of cylinders, tanks, compressors, etc.
Added reverse shifting Sprint Distance Calculator
Fixed bugs with Sprint Distance time calculation
Fixed bug with Ratio & Distance Calculator
Miscellaneous bug fixes
Minor UI changes
As always, if you have any questions on how to use the spreadsheet or find any problems with the calculations, please don’t hesitate to reach out either in this thread topic or by PM.
Interesting. Did you enable macros? I downloaded it fresh on a new computer and it seemed to be working fine. Can you send a screenshot so I can see what inputs you’re using and what error you’re getting
Oh yeah, that would definitely do it. The Sprint Distance Calculator uses VBA code to run the timing simulations, so copying over to Google Docs wouldn’t bring that code along too
Could you put a note somewhere on the sprint distance calculator tab explaining what the different “x”, “v”, “a”, and “slip” values on the chart mean? Charts/formulas that don’t define their variables (in plain english) are one of my biggest pet peeves.
Sean is right. I assumed those were pretty standard variable names, but I guess some people might not pick up on that right away. Slip shows when the wheels are slipping (i.e. the robot breaks traction). I included a key explaining these terms for whenever I post the next release.
Version 3.2 - A few more bugfixes and improvements:
Fixed incorrect NEO motor data
Redesigned imperial metric selection to be more intuitive
Updated COTS sprocket and belt sizes; removed inaccurate pulley and gear sizes
Chain/Belt C-C Calculator now includes the suggested C-C addition and also automatically populates the correct pitch based on the chain/belt type selected
Can now use stall voltage as an input for the Mechanism Calculator
I just downloaded a fresh copy and it didn’t give me any errors. Make sure you enabled macros, otherwise you will certainly get errors (specifically #NAME errors). If that’s not the problem, can you send me a screenshot of the sheet (either posted here or by PM).
There are three inputs for that for each action. Time Per Cycle defines how much time between each cycle start (i.e. from extension to extension, or period). Start Time and End Time are pretty much exactly what they sound like: what time does the first action happen and when does the last happen. So for example, if your action starts after autonomous and ends at the start of the endgame you should put 15 for Start Time and 130 for End Time (20s before the 150s match ends).
The model makes a few assumptions. The “simulator” has a resolution of 1 second. Any action that fires less than once per second shows both extension and retraction at the beginning of the cycle (worst case scenario). An action that happens more than once a second happens that number of times per second, every second. You won’t see the sawtooth shape on the graph because it’s interpolating between second marks, but in reality it will be there.
As I’m writing this, I found a bug in the calculation that makes it not work for non-whole number periods greater than 1. I’ll be pushing an update to fix that soon. In the meanwhile, you can use multiple of the same actions with different periods to emulate the same thing.
I’m trying out a new method for hosting my spreadsheet that will allow me to push updates so the most recent version is at the top of the page rather than having to find the most recent version in the middle of the thread. I’m hosting the Excel document on GitHub, and using GitHub Pages to make an auto-download page. If this works well, I’ll be using this to host future versions of my spreadsheet (and possible other white papers I post that I plan on updating in the future).
Also, I just realized that I fixed the bug with non-integer period timing on the pneumatics tab but put the solution directly into v4 (in alpha development) rather than posting it as a separate bug fix. So I’m now releasing v3.5, which you can download from the website here.
Hi, I’m having trouble on the sprint distance page. When I download the spreadsheet and I open it without activating the content I can see the graph with its values but when I activate the content all the information disappears. Even when I’m trying to modify some values the graph doesn’t react.
Sorry it took so long to get back to you, I just got back from Detroit yesterday. I tried downloading a fresh copy of the design spreadsheet from the website and the Sprint Distance Calculator worked fine for me. It does take a few seconds to re-draw the graphs, possibly more if you’re working on a low-power computer. Even if the graph doesn’t update, the outputs should still be correct; they are calculated independently from the graph. If the Sprint Distance Calculator still isn’t working for you, I’ll recommend ILITE’s Drivetrain Simulator, which does something similar to my Sprint Distance Calculator, but uses slightly different formulas.
If there are any actual mechanical engineers (i.e. who’ve actually finished their degrees) who are up to date on their mechanical design formulas, I’d love it if you could PM me. I need some help/advice with formulas on a new calculator and want a more expert opinion.
