Research on Adaptive Tracking Isothermal Layer Based on Towed System

Isothermal layer's adaptive tracking was studied for shipboard towed muti-parameters profile sampling system. Based on the theoretical model of cable and towed body, three important hydrodynamic parameters were optimized using towed data from sea trials, and a semi-analytical physical model of towed system was constructed. According to the idea of sensing-deciding-acting-feedback, the operation of the towed system was simulated in the field of temperature data from interpolated towed sampling. By using the difference between the sensed temperature and the isothermal layer's temperature, the expected depth of towed fish was adaptively decided, then it was responded by PI control law on the basis of constructed model of towed system so that the isothermal layer could be tracked. The tracking result of 26.5 ℃ isothermal layer is illustrated in the numerical simulation.