Fuzzy controller design for synchronous motion in a dual-cylinder electro-hydraulic system

In this paper, an integrated fuzzy controller is proposed to achieve a synchronous positioning objective for a dual-cylinder electro-hydraulic lifting system with unbalanced loadings, system uncertainties, and disturbances. The control system consists of one-fuzzy coordination controller for both cylinders and an individual cylinder controller, comprised of a feedforward controller, and a fuzzy tracking controller, for each of the hydraulic cylinders. In the integrated fuzzy controller design, the fuzzy coordination controller is responsible for dispatching motion synchronization commands to the individual cylinder controllers. Each cylinder controller then adaptively enforces the position tracking to its controlled actuator. The experimental results show that the proposed integrated fuzzy controller design can effectively achieve the objective of position synchronization in the dual-cylinder electro-hydraulic system, with maximum synchronization error within ±4 mm.