The Control Strategy Of Round Dish-shaped Underwater Glider

Marine monitoring plays an important role in marine development process. This article proposes a new dish underwater glider. This glider has the following advantages, such as long navigation time, wide detection range, low noise and no reliance on its mother-ship, also owing to the disc-shaped design it has enhanced flexibility and anti-winding characteristics. Meanwhile due to full wing-body structure, the dish underwater glider gains power and speed to glide forward, entirely relies on its own buoyancy. When floating and diving, it only needs pose adjustments at the highest and lowest points of its cycle to balance buoyancy and gravity, during any other gliding process,it requires no adjustment. However, it is difficult to keep underwater glider in a linear navigating motion, let alone simulate the equations of its motion. Therefore this article adopted a specially designed fuzzy PID controller as a control method for the disc underwater glider.Firstly, this article analyzed the underwater movement of the dish underwater glider, established the coordinate system as well as the improved axial translation and rotation equations using reasonable assumptions and simplifications. Eventually obtained a relatively sophisticated motion equation. Considering the difficulty when applying control method made for motion equations on disc underwater gliders, this article proposed PID control method.Secondly, it proposed a fully symmetric dish underwater glider design, including exterior design, buoyancy control system, center of gravity control system, automatic control system. Elaborated the implementation of various functions and subsystems. Made PID control feasible, also made it possible to adopt fuzzy control to achieve further precision of PID control.Finally, for motion control strategy of the underwater glider, independently designed a fuzzy PID controller as its control scheme, according to the characteristics, adopting fuzzy parameters control method to combine fuzzy control and PID control, using error and its change rate to realize real time correction of proportional, integral and differential coefficient. In addition conducted water experiment and simulations, and ultimately accomplished control parameters for PID control with fuzzy control. Avoided the sophisticated motion equations. At the same time, the use of fuzzy control method compensated for the lack of operating experience, also-promoted the control precision of disc underwater glider, given better price and accuracy to the underwater glider, proved its important position in the future marine competition.