Research Of The Wing With Flexible Trailing Edge For Underwater Glider

The diversified monitoring tasks and more and more complex working environment of marine observation put forward more and higher requirements for the motion modes and performance of underwater gliders.As one of the core components,the wings play a decisive role in the navigation performance of the underwater glider.At present,most of the wings used in the glider are flat fixed wings,which show no difference under different motion modes and have a poor self-adaptive ability.In order to improve the motion performance of the underwater glider,the wing design with flexible trailing edge and an adaptive control strategy is proposed in this paper.The research results have opened up a new prospect for the development of a new type of high performance underwater vehicle.Taking the flat wing of "Petrel" underwater glider as an object and based on the judging method of underwater vehicle motion stability,the discriminant formula for navigation economy,motion stability and mobility of the underwater glider during variation of the trailing edge is deduced.Based on this formula and combining the computational fluid dynamics(CFD)simulation results,this paper discusses the effect of the change of the flat wing's trailing edge bending direction and angle on the glider's navigation economy and stability in the vertical plane.The effect of the differential variation of the two wings on the glider's mobility and stability in the horizontal plane is discussed as well.The suitable variation range of the trailing edge bending angle at different angles of attack is obtained.The results show that the suitable deformation of the trailing edge can greatly improve the glider's navigation economy and mobility,and has little effect on the overall stability.The research findings provide basic data and theoretical support for the conceptual design of flexible wing in the subsequent research.According to the above results,the hydrodynamic characteristics of the flat rectangular airfoil and NACA series airfoil are compared and analyzed,and the basic airfoil for design of the wing with flexible trailing edge is determined.Two driving schemes for the trailing edge deformation of the wing are proposed: the intelligent material MFC(macro fiber composite)is selected for flexible drive,and cable driving is selected for flexible transmission.Based on the two driving schemes,the adaptive deformation strategy of the trailing edge deformation of the wing is developed.In addition,the test results show that the two schemes can both achieve the required deformation of the trailing edge.For the following work of the wing with flexible trailing edge,a small-scale underwater glider capable of carrying the flexible wings is developed for testing,whose prototype is the “Petrel” underwater glider in the laboratory.The glider includes the main body,a pitch motion unit,a control unit(control circuit)and the flexible wing unit.The result of the tank experiment proves that it is feasible for the developed experimental scale glider carrying the flexible wings to perform underwater motion experiments.