Dynamics modeling and comparative analysis for underwater gliders considering different ranges of attack angle

The underwater glider, which relies on buoyancy and attitude adjustments to achieve spatial motion, is an energy-saving observation platform for ocean phenomenon. Accurate dynamic models have important guiding significance for performance evaluation and controller design of the glider. This paper takes the Petrel glider as the research object, and establishes four types of dynamic models considering different ranges of attack angle, which has never been reported before. The model difference is mainly reflected in the viscous hydrodynamic equations obtained by using polynomials to fit computational fluid dynamics (CFD) simulation results. Then, some numerical cases are given to study the dynamics response difference of these models considering the ideal working condition and complex water current environments, respectively. The results indicate that there is not obvious dynamics response difference under the steady-state gliding condition, and the difference mainly occurs during the glider motion transition stage. Under the complex water current conditions, the dynamics response difference will be very significant, and the traditional dynamic models may exhibit the non-convergence issues. The comprehensive model established in this paper, which fully considers the ranges of attack angle, can better simulate the dynamics behavior of the glider and can provide certain theoretical guidance for actual application.