Intelligent control of diving system of an underwater vehicle

Abstract

The design of a depth control of an underwater vehicle is described in this thesis. A mathematical model of an underwater vehicle namely, Deep Submergence Rescue Vehicle (DSRV) is developed. Four types of controllers are designed which include PD, Pole Placement, Conventional Fuzzy Logic (CFLC), and Single Input Fuzzy Logic (SIFLC). The CFLC gives satisfactory results. However, the design is complex because there are a large numbers of rules and parameters that need to be tuned. To overcome the problem an alternative to CFLC known as SIFLC is proposed in this thesis. The controller is based on Signed Distance method, which reduces the numbers of rules and tuning parameters without compromising its performance. In effect it reduces the system to a SISO model which results in simple tuning. Faster computation is also expected because the controller can be constructed using a look-up table. All of the four controllers are designed based on overshoot, settling time, and steady state error specification criteria. Based on these criteria, a comparison study is performed to show the effectiveness of the designed controllers. All of the four controllers other than PD controller are found to give satisfactory results. The proposed SIFLC exactly resembles the CFLC in transient and steady state response which shows the effectiveness of the designed controller.