For example, a visitor's backpack might suddenly fall to the ground, or a child might fall down. A robot has to be able to reliably avoid these unexpected obstacles, or even stop abruptly to avoid inadvertently stepping on or crushing someone.
譬如遊客的背包突然掉下來、或有小朋友跌倒，對於這些不是預期中的行為，機器人要能穩定的閃躲，甚至馬上停下腳步以免誤踩或跌倒壓傷人。