Application of PI/PID Control Method to Electro-Hydraulic System

Abstract

The electro-hydraulic system has been used in various fields such as robot manipulator and anti-lock braking systems. It has several significant features that its high power-to-size ratio, high stiffness and high payload capability. For Now, the research for the electro-hydraulic system control method and its application system has been developed.

In this thesis, the goal can be represented in two words, easiness and simplicity. The proposed algorithm should be easy to implement, and designed to save computational burden. And the simplicity means that the algorithm should operate by using minimized design parameters.

In order to achieve the goal, position control method, such as Pre-tune algorithm and Post-tune algorithm, and force control method were proposed. Those algorithms were implemented for electro-hydraulic linear actuator.

Pre-tune algorithm aimed at how to get critical gain and period simple and easily. It was designed to get both critical gain and period by comparing the input and output responses. Post-tune algorithm was suggested to tune the gain by using the square rule. Barrier PI control method was proposed for force control. By using the physical constraint of actuator, barrier PI controller could be designed and the scheme was verified by experiments.