求翻译：鉴于传统的液压教学实验台存在着内容固定、功能单一、管路已连接好不易修改、实验以演示为主、学生动手机会少等缺陷。针对这些缺陷，本文主要设计的液压实验台是在传统实验台的基础上主要针对液压系统的原理，和电气控制系统以及实验台装置的设计，以及实验所需要的各类阀类元件和传感器以及液压系统所必需的附件等的计算和选择。是什么意思？

In view of the traditional hydraulic teaching experiment, there is a fixed, single function, the pipeline has been connected is not easy to modify the experiment to demonstrate the students hands-on opportunities for defects such as. For these shortcomings, this paper designed hydraulic test bed is