and

displacement

curves, this reflects system’s operation more intuitive.

According to analysis of simulation results ， the hydraulic cylinder's speed

vibrated larger during operation. In this paper, PID control algorithm has been added

to the system, used Integral separation PID control method for the hydraulic system’s

simulation and analysis. The results showed that after adding PID control method ，

system stability has been improved, and reflected the good performance.

Keywords:

Hydraulic Elevator;

Double straight-top;

three-tier synchronous hydraulic

cylinder;

Dynamic Simulation;

PID control