Murphy's law

every single time I run auton.


During my skills auton, a ball somehow became stuck under my intake plate. I have no idea how it happened. My intake plate has around 1/2” of clearance.

I agree Murphys law is largely a sampling bias. We don’t count every scenario and how many ended in failure, we just remember the failures.

There is a second component though. The planning fallacy alludes to it.

A clue to the underlying problem with the planning algorithm was uncovered by Newby-Clark et al., who found that

  • Asking subjects for their predictions based on realistic “best guess” scenarios; and
  • Asking subjects for their hoped-for “best case” scenarios . . .

. . . produced indistinguishable results.[5]


This is true, it’s obvious that everything’s that can go wrong doesn’t go wrong, if this was the case there would be a massive earthquake every couple seconds, or Yellowstone would have gone off, but this post is basically asking what went wrong, for the first time ever, at a competition

I don’t know about you, I thought @Connor1814A and I were having an interesting conversation.

I agree, all I said was that I agreed with you and explained that the I did not take Murphy’s law litteraly when creating this thread, just the general premise of something going wrong at the worst moment

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the thing is they were side by side and i punched the puncher like crazy and it burnt out
we still won tho

dude this happened to me during a match and it moved to an empty spot between the bracing and the plate holding up the bar behind the intake

  1. One time the auto code made the bot spin in circle and aim for my driver instead of the flags. This is most likely due to the vision auto aiming code giving false command. This same set of code has been working for many tournaments and many lighting situations. And it worked well throughout the day of the competition until that moment :blush:.

  2. At LA state competition’s final game, one side of the alliance got DQed after ending the game with a winning score of 25 to 9. That is very unfortunate and surprising. But life happens :joy:

  3. One time the top of our cap flipper got stuck in the net behind the flags 30 seconds into the match. We had to put down the joystick since we were not able to get out of the net.


ah yes 45464Z sure was happy about that one.

Last year my teammate forgot the bag with batteries and chargers at home. It was our first competition and we didn’t know what to do. We were ready to cry.

A high school team gave us their extra battery and another parent let us charge laptop with their charger.


In NBN, at the US Open with @technik3k, our robot was doing pretty well in qualification matches and a few other top teams were interested in alliancing with us. As we were waiting in line for skills, we left our robot turned on, resting on the very narrow queueing table. One of the joysticks snagged our team member’s shirt and the robot drive right off of the table and landed on its hood. We stayed up late at night trying to fix it, and thought that it would be a good idea to add an extra unused motor to the flywheel. We could not return it to its original condition and all of the potential alliances we had fell through. :frowning_face:

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one time we let our captain pack for our comp. here’s a list of the things we didn’t have:

  • rubber bands (rather unfortunate, we had a catapult)
  • nuts
  • screws
  • AAA chargers
  • orange USB cord
  • notebook
  • wrenches
  • competition switch
  • Ethernet cable
  • spacers
  • power strip
  • spare motor controllers
  • spare motors

Lets just say the generosity of other teams certainly came in handy…


Funny, but I have absolutely no recollection of the robot being turned on. When the students went into the skills queue, I stayed behind. I noticed that the queuing tables looked very narrow, probably, no more than 16" - barely enough to place a robot and I remember that subconsciously I didn’t like that. However, before I could realize what it was bothering me, the robot went tumbling to the ground.

In retrospect, it is obvious that it was combination of several human errors that made the fall very likely, almost inevitable. Event organizers had no idea that such narrow tables were totally inappropriate for robots mostly equipped with easily sliding omni wheels. My team was very excited by the earlier wins and wasn’t experienced enough to recognize potential hazard of narrow tables and, also, didn’t think much about leaving the robot turned on.

As a result of the fall, flywheel went out of alignment and all carefully tuned programming routines were ruined for the rest of the competition. To the team’s credit they were able to salvage at least some of the flywheel performance. Even though balls were flying all over the place @_Colossus managed to compensate for the faulty hardware with his driver skills and top our best score for the season.

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If I understand correctly, @tabor473’s point is that Murphy’s law is not the law of the nature but our subjective interpretation of why unfortunate events tend to happen as they do. That is true.

Human brain is not very accurate with the probability math. It applies very fuzzy logic, at best, mixing real inputs and the desired outcomes, compounded with our natural tendency to conserve action (read: laziness). Sometimes we make irrational decisions that end up working well, but many times they could lead to catastrophic results.

To ensure high probability of positive outcome, even when critical decisions are made by actors with potentially irrational internal logic, you need an external system that could reliably compensate for that. Large organisations like NASA could employ rigorous processes and checklists based on the studies like the one cited by Tabor, but even they are not immune from human errors that lead to catastrophic results from time to time.

I find that one of the simplest and most effective ways to compensate for the irrational probability math, that our brains do, is to employ equally irrational conclusions of the Murphy’s Law.

You may know that it is not true that everything that could go wrong will go wrong. But you better subconsciously believe that anything important could fail at any time. Then, when it will be time to choose if you should test or not test a sub-system or autonomous, that never failed at home before, and that belief will be what prevails over your natural laziness, and you run the test anyway, then your chances of success will substantially increase.

It is much easier and effective to believe in Murphy’s Law, than to study psychology for many years just to understand a small fraction of the ways in which human thinking process may lead to the erroneous results.


If you believe in Murphy’s law you want BO3, if you don’t your fine with BO1, change my mind

We’re engineers, not brain surgeons!


U right

But we have to operate our robots with V5 brains.

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But if you tamper with the brain your breaking the rules