Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

Poka Yoke

en.wikipedia.org

Post reply on HN
Print view View original

51–60 of 64 posts

Re: Poka Yoke

#51

Post by akavel »

chriswarbo wrote: post #36
DavidPeiffer wrote: post #14

Earlier quoted context omitted.

I'm an industrial engineer, so this is all right up my alley! My favorite example is a two-part foam injection machine. They needed to change the injection head, and accidentally put it on backwards. The parts mixed and worked their way back in the supply lines, solidifying along the way. Hundreds of thousands of dollars in lost productivity, multiple weeks to get it fixed. They promptly switched the coupling so it w…

A Proton rocket launch failed in 2013, supposedly due to sensors being installed backwards: https://en.wikipedia.org/wiki/Proton-M#Notable_launch_failur... The Genesis sample-return capsule crash-landed due to the accelerometer controlling the parachute deployment being installed upside-down: https://en.wikipedia.org/wiki/Genesis_(spacecraft)#Mishap_In...

And notably, as a kinda higher-level challenge towards poka-yoke...:

The improper installation apparently required some considerable physical effort, which, somehow did not raise any alarm at GKNPTs Khrunichev's assembly plant in Moscow. (...) By July 13, investigators simulated the improper installation of the DUS angular velocity sensors on the actual hardware. As it turned out, it would be very difficult to do but not impossible. To achieve that personnel would need to use procedures and instruments not certified either by the design documentation or the installation instructions. As a result, the plate holding the sensors sustained damage. Yet, when the hardware recovered from the accident was delivered to GKNPTs Khrunichev, it was discovered that the nature of the damage to the plate had almost exactly matched the simulated version.

(via: http://www.russianspaceweb.com/proton_glonass49.html)

In other words: poka-yoke, meet hammer...

(To make it clear, I absolutely love the idea of poka-yoke, and find it great help in software development as well; still, I find the story both hilarious and educative ;) )

Re: Poka Yoke

#52

Post by AussieWog93 »

4gotunameagain wrote: post #49
AussieWog93 wrote: post #16

Slightly different to what is described here, but one of my pet peeves is the "nuclear button" features that devs put in their software - ie easy to activate features that add marginal utility to specific niche workflows but cause irreversible damage to everyone else. Firefox deleting every single one of your pinned tabs on close if you have a second window open is an example of this, as is YouTube jumping to a diffe…

"as is YouTube jumping to a different part of the video every time you bump one of the numerical keys on your keyboard. " Niche workflows? This is one of the most useful features! :)

You animal, you!

Re: Poka Yoke

#53

Post by glugc »

gberger wrote: post #48
AussieWog93 wrote: post #16

Slightly different to what is described here, but one of my pet peeves is the "nuclear button" features that devs put in their software - ie easy to activate features that add marginal utility to specific niche workflows but cause irreversible damage to everyone else. Firefox deleting every single one of your pinned tabs on close if you have a second window open is an example of this, as is YouTube jumping to a diffe…

My personal favourite is the "clear" button at the bottom of forms, right next to the "submit" button.

I haven't seen a form with a clear button in 20 years.

Re: Poka Yoke

#54

Post by kazinator »

kevinstubbs wrote: post #41
kazinator wrote: post #15

Earlier quoted context omitted.

Probably because ポケ is, causing katakana contagion of the 除け part. (I made up "katakana contagion"; don't bother searching.)

"katakana contagion" sounds so cool. I'm disappointed it's not a real thing. Could you explain what it means?

Contagion is the spreading of some property from one entity to another by come form of contact.

For instance "floating-point contagion" in computing which refers to a situation when an exact number and inexact number are combined together in on operation, and the exact number is first coerced to inexact. E.g. 0.5 + 1 is carried out as 0.5 + 1.0: the integer 1 value becomes 1.0.

Re: Poka Yoke

#55

Post by auxym »

totetsu wrote: post #24

These kind of electric paper cutters are common in Japanese school copy rooms. As they could easily cut fingers off, they require you to close the top cover and then both hands to operate the cut switches. (only after you've turned a big red arming switch) https://nihonkiki.com/products/detail.php?product_id=4993

Common on industrial stamping presses also. Operator loads metal sheet, then needs to activate the press with two physical buttons, separated with enough distance that it can only be done with two hands.

Re: Poka Yoke

#56

Post by cameronh90 »

SV_BubbleTime wrote: post #44
Doxin wrote: post #30

Earlier quoted context omitted.

Yes. Always. If your transmission is defective somehow you don't want the car to lurch when you start it.

Automotive EE here… I don’t think this is correct. If you are talking pre-electronic shift, your transmission still has position sensors and the engine or trans control module will not allow start while engaged. All vehicles have interlocks for this. Post electronic shift, it’s no question at all. You would need at least two errors in two completely separate circuits to get the vehicle to start in gear. Believe it or…

I may be misunderstanding what you're saying, but many modern cars I've driven will still allow themselves to be started in gear.

It happened to me quite frequently until I built up the muscle memory for always starting with the clutch in, and occasionally still does if I forget (I drive a lot of hire cars).

Re: Poka Yoke

#57

Post by leghifla »

chriswarbo wrote: post #37
Zecc wrote: post #32

Earlier quoted context omitted.

When writing and running SQL one-offs interactively, I will surround it with `if 1 1 begin end` or comments, or add syntax errors at the top so that I won't accidentally run it without first selecting the part I want to run. I should get into the habit of writing `begin; rollback` instead for extra-safety. And I always write the WHERE clause before the DELETE or UPDATE keywords.

> And I always write the WHERE clause before the DELETE or UPDATE keywords. I sometimes get nervous typing 'rm -r' commands, since it starts with a very broad path, and only narrows-down as we type more, e.g. if we hit enter prematurely when typing 'rm -r ~/Downloads/archive.zip' we might delete our entire home directory, or all of our downloads. For this reason I often prefix dangerous steps with 'echo'; once I'm co…

When I was still a student, I accidentally erased all my project source code with:

rm * .o

I was puzzled by the message ".o: No such file", and then understood why...

Now, I always start with ls and if satisfied of the output, replace ls with rm

Re: Poka Yoke

#58

Post by kristofferc »

DavidPeiffer wrote: post #14
sokoloff wrote: post #12

One of my favorite examples is the control lock on some light aircraft. Aircraft are often parked outside and in windy conditions, you want to prevent the control surfaces from being banged around, so you put in control locks. You also don’t want aircraft trying to take off with locked controls (such as the G-IV mishap at Bedford* a few years ago). Enter the control lock that blocks the starter: https://www.csobeech.…

I'm an industrial engineer, so this is all right up my alley! My favorite example is a two-part foam injection machine. They needed to change the injection head, and accidentally put it on backwards. The parts mixed and worked their way back in the supply lines, solidifying along the way. Hundreds of thousands of dollars in lost productivity, multiple weeks to get it fixed. They promptly switched the coupling so it w…

Another (smaller) example is the detachable controllers on the Nintendo Switch ("Joy-Con") which are very hard to remove if you accidentally reattach them upside down.

Re: Poka Yoke

#59

Post by ndsipa_pomu »

tux3 wrote: post #46
chriswarbo wrote: post #37

Earlier quoted context omitted.

> And I always write the WHERE clause before the DELETE or UPDATE keywords. I sometimes get nervous typing 'rm -r' commands, since it starts with a very broad path, and only narrows-down as we type more, e.g. if we hit enter prematurely when typing 'rm -r ~/Downloads/archive.zip' we might delete our entire home directory, or all of our downloads. For this reason I often prefix dangerous steps with 'echo'; once I'm co…

I always write rm -rf for this reason (I was surprised to learn that on some systems, the flags are in a fixed position, at the start!)

One reason for having the flags before the is so that you can terminate the flags by using '--'. This is especially useful to prevent dubious files being expanded that might start with '-' and be interpreted as flags that leads to unexpected results.

Re: Poka Yoke

#60

Post by lxgr »

luispa wrote: post #19

This was one of the best things I learned at my first job. The capability of finding an error-proof solution is so satisfying. One of the best examples I know is: - The Heart Valves, are an error-proofing example in nature that prevent the back-flow of blood

Arguably a (valve-based) pumping system without valves wouldn't be considered error-prone but rather non-functional? (I might be missing something, though, since I don't really know whether heart valves are dual-purpose like that.)
Post reply on HN