Dynamical Behavior And Control Strategies Of The Flying Wing Underwater Glider

Underwater glider is a kind of autonomous underwater vehicle with low costs,low noises and strong cruising power, which has broad application prospects in ocean-environment research and marine-resource detection. The appearance of regular underwater glider consists of revolution hull, horizontal tail and appendage. Due to the hull producing almost zero lift during motion, its glide ratio is limited. Flying-wing underwater glider is a special-strutured kind of underwater glider, which, in order to obtain larger glide ratio, produces lift on body by concealing the hull inside the hydrofoil to integrate the wing and the hull. Due to the effect of underwater glider’s hydrodynamic performance on its motion performance, in order to sufficiently understand its dynamic behavior and control characteristics, this paper conducts research on underwater glider’s control strategy and dynamic analysis.First, based on Newton-Euler Equation, two dynamic models of Flying-wing underwater glider are established, one of which is the steady-state analysis model used for steady-state analysis and motion performance report, the other is the controller design model used for motion real-time simulation and controller design. In this process, front-and-back asymmetry factors of Flying-wing underwater glider, as well as the effect of buoyancy control device on carrier posture are taken into consideration. Based on dynamic models, steady motion analysis methods for Flying-wing underwater glider in space and lengthways planes are researched. With the principle prototype as the research object, the solution procedure of model parameters are introduced,and the viscous hydrodynamic fitting formula is proposed which takes space coupling effect into consideration. Then,steady glide motion is analyzed and forecast, therefore the relationship between speed, angle of attack, angle of pitch and net buoyance, longitudinal centre of gravity is established, the dynamic characteristics of Flying-wing underwater glider are summarized. It is indicated by forecast results that,Flying-wing underwater glider can perform high-efficiency motion with high glide ratio.Aiming at the feature that control time-delay exists in the motion procedure of underwater glider,intergating vague technology and S control method,a vague non-linear PD controller based on T-S reasoning is designed. A simulation experiment is conducted on glide trajectory control in longitudinal plane and compared with that of S plane controller and PID controller,the results proved the advantages of vague non-linear PD controller.Finally, based on theoretical research, the motion control system is designed and successfully applied to principle prototype. The results of tank-test research based on the prototype validates the effectiveness of dynamic model motion performance forecast. By combining theories and experimental researches, this paper uncovers the motion characteristics of flying-wing underwater glider, and lays foundation for its practical application.