Design of Two-Level Fuzzy Controller in Automatic Hydraulic Loading System

Pressure force loading experiment for shell of spacecraft is significantly important for safe flying. Mathematic model of automatic hydraulic loading system for the shell of spacecraft is developed in this paper. In accordance with the highly nonlinear characteristic of plant, a two-level fuzzy controller is applied. The first level is a traditional fuzzy PD controller, and the other level can adjust output proportional factor of fuzzy PD controller based on the pressure of system. In order to avoid rule explosion in designing of high-dimension fuzzy controller, complement fuzzy rules is constructed to approximate linear controller in small error scale, then ant colony algorithm is employed to select optimize fuzzy rule set in complement rule base, and the time window is adopted in ant colony algorithm to ensure the continuous of selected rules. Experiment results show the good performance of this approach.