Study Of Longitudinal Motion Control Strategies For Underwater Gliders

As an autonomous underwater vehicle,the Underwater Glider is widely used in marine environment observation,military reconnaissance and other fields due to its low power consumption and long range.However,due to the complex operating environment of underwater gliders,and the high degree of nonlinearity of the model,it is difficult to achieve high-precision motion control,which makes it easy to produce problems such as longitudinal inclination oscillation and other interference with the observation accuracy,even leading to the phenomenon of observation data failure,thus hindering the application of underwater gliders.To this end,this paper focuses on the Petrel 200 Underwater Glider developed by Tianjin University to conduct dynamical modeling and simulation analysis,and carries out longitudinal motion control strategy research on the longitudinal inclination oscillation of the underwater glider,with a view to improving the motion control accuracy of the underwater glider and meeting the requirements of ocean observation.The main research work and results are as follows.Based on the Newton-Euler equation,the Petrel 200 Underwater Glider is dynamically modeled,then the dynamics model of the longitudinal motion of the underwater glider is subsequently established,and the analytical solution of the longitudinal steady-state gliding is obtained by solving the set of equations.Simulink is used to model and simulate longitudinal inclination oscillation to demonstrate the accuracy of the underwater glider dynamics model.The analysis of the Petrel 200 Underwater Glider’s longitudinal inclination oscillation was carried out,a conjecture that the unreasonable parameters of controller may cause the longitudinal inclination oscillation of the underwater glider was proposed by analyzing the test data,and the longitudinal inclination oscillation was modeled and simulated by Simulink to verify the rationality of the conjecture.The established Simulink model,which accurately reflects the dynamics of the Petrel 200 Underwater Glider,was validated by comparing test data and simulation results.In order to solve the problem of longitudinal inclination oscillation of underwater glider,a fuzzy PI controller was designed and simulated for a variety of working conditions,and the control effect was analyzed and compared with that of PID control,taking the overshoot and response time as evaluation indicators,the results show that the fuzzy PI control is superior to PID control in terms of stability,accuracy and speed.The energy consumption model of the pitch attitude adjustment system for Petrel200 Underwater Glider was established.Based on the Simulink model,the energy consumption of the attitude adjustment system with pitch oscillation,PID control and fuzzy PI control was calculated respectively under the same initial conditions,and the results showed that the fuzzy PI control has the advantage of low energy consumption.