First introduce the working principle of the inchworm in-pipe robot based on unilateral movement mechanism, and then an equivalent system model is founded after simplifying the whole robot system.
介绍了基于单向运动机构的伸缩式管道机器人工作原理，对管道机器人整机系统进行合理简化，得到等效系统模型。
From the Angle of wave motion optics, on the principle of Huyghens, explaining the light of refraction. Simplifying the picture of the light of refraction and then getting a simple drawing method.
从波动光学的角度，用惠更斯原理解释了光的折射现象，根据惠更斯原理所作的折射光线进行简化，得出较为简单的作图方法。
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