| Popis: |
In this paper, a fuzzy logic based control system for an undersea vehicle is proposed, in order to improve the response of the vehicle to commands as well as to make it robust against speed changes and environmental disturbances. After a brief introduction of the dynamical model of the undersea vehicle and the fundamentals of fuzzy logic control, the construction of the fuzzy logic controller for the vehicle is set up, in which depth and pitch rate are chosen as input linguistic variables, and the deflection of the sternplane is the control variable. Performance evaluation of the fuzzy logic controller for the vehicle is carried out at three different speeds chosen from the whole speed region. The evaluation includes: 1) response of the vehicle with the fuzzy logic controller to a depth command, 2) robustness of the fuzzy logic controller to speed variation and 3) robustness of the fuzzy logic controller to wave induced disturbances. The calculation results show that the depth response reaches the command's value without oscillation and final error at all speeds, and the designed controller demonstrates good robustness against parameter changes and provides effective disturbance rejection from waves. |
