←back to thread

181 points EndXA | 1 comments | | HN request time: 0.197s | source
Show context
PinguTS ◴[] No.40728639[source]
I know, this is an old paper, but I don't follow the this assumption:

> The terms jerk and snap mean very little to most people, including physicists and engineers.

Almost 20 years ago we defined jerk into our standards for lift applications. I know jerk is an important parameter for any modern rotating machine that includes gears.

While in lift applications it is known as the roller coaster effect, people in different parts of the world have a different taste on when they want to use a lift. I know I over simplify when I say, that American people want to have the gut feeling when riding a lift, especially an express lift in those high buildings. In difference in Asian countries the lift ride must be smooth as possible. They don't like to have the feeling of riding a lift at all. In Europe it is something in between. Lift manufacturers have to respect those (end) costumers otherwise the are not chosen.

The same in any rotating machine with some sort of gears. Because jerk and those higher orders contribute to the wear and tear of gears. As you want to have longer lasting gears many modern machine manufacturers limit those parameters to reduce wear and tear. So, with a little software change I can demand a higher price because service and maintenance can be reduced.

replies(6): >>40728717 #>>40729011 #>>40729341 #>>40729794 #>>40731202 #>>40734361 #
account42 ◴[] No.40728717[source]
> American people want to have the gut feeling when riding a lift, especially an express lift in those high buildings. In difference in Asian countries the lift ride must be smooth as possible. They don't like to have the feeling of riding a lift at all. In Europe it is something in between

How representative are these stated preferences actually of the population. I'd imagine that the individual preferences vary greatly from person to person and also change with age.

replies(3): >>40729103 #>>40729400 #>>40734373 #
1. codexb ◴[] No.40734373[source]
I'm an American.

My thoughts are that I'd prefer to spend as little time as possible in an elevator and would rather spend that time doing other things.

If I don't feel the elevator moving, then it's moving too slowly and wasting my time.