设计背景:电梯,特别是自动扶梯成了生活中不可或缺的一部分。电扶梯一般分上行与下行两部分,根据乘电梯的人数来调节电动机功率,使自动扶梯始终保持匀速运动。前不久,深圳就曾经出现由于乘电梯的人数过多,电机功率不足而导致电梯倒滑,造成人员伤亡的事故。于是我想,在我们增强安全意识的同时,能否把扶梯下行时,将人的重力势能转变成扶梯上行的动力,从而达到省电节能的目的呢? Design background: Elevators, especially escalators, have become an integral part of life. The escalator is generally divided into two parts: upstream and downstream. The motor power is adjusted according to the number of people taking the elevator, so that the escalator always moves at a constant speed. Not long ago, in Shenzhen, there have been accidents caused by too many people taking the elevators and insufficient motor power to cause the elevator to slide backwards, causing casualties. So, I think, when we increase our awareness of safety, can we make the escalator down and turn people’s gravitational potential into escalators’ upward power, so as to achieve the purpose of energy saving?