Recently, I felt so frustrated of being a student graduated from dep. of mechanical engineering. Things went like that: my father hoped my brother and I design a mechanism for automatically opening and closing up two plates which are pinned together at the edges of each one, just like the lid of a copy-machine and the glass matches with it. But the differences between these two are the accuracy and the weight of the lid. This mechanism has to ensure the relative position of two plates while closed can only change within several micro-meters after thousands times of movement. And the weight of the lid plate is about 25kg.
What let me feel down is that, thought this should be sort of simple mechanism in actual world which is only concerned with static mechanics, but however, it haunted me for these three weeks. I even could not guarantee that the analysis of FBD(free body diagram) I drew is correct, because the actual mechanism which assembled by parts made as my design doesn't work! Punch! Reviewed former design, modified those parts, and tried again, but still failed. Punched again.
Now I totally redesign the mechanism, and hope it will work.
Actual world is always more terrible and complex than what we learned in textbook.
by the way, the gear pic about this article has nothing about my design. XD