Design And Implementation Of Control System For Mini Portable Underwater Vehicle

The development of mini underwater vehicle is low in cost,short in cycle,and easy to carry and use,can help human to complete the task of underwater work so that it has broad application prospects.But it is greatly affected by water flow and its stress condition is complex.To ensure that it can achieve efficient motion control in complex underwater environment,it is important to design a motion control system with excellent performance.Firstly,in order to obtain the motion model that needed by simulation research,the stress condition of mini underwater vehicle is analyzed,and its spatial motion equation is deduced.The spatial motion is decoupled into horizontal and vertical planes.The small underwater vehicle's bow motion model and depth motion model are derived respectively according to the dynamic equations in different planes.Secondly,according to the working needs of the mini underwater vehicle,the hardware system and software system are established,the overall structure of the hardware system and the working principle of the main components are analyzed,the composition of the software system and the architecture flow of the open-source underwater vehicle control software used are explained;The motion control algorithm of the mini underwater vehicle is studied,designs the cascade PID control structure for heading control and depth control,proposes a fuzzy PD-PI control algorithm improved by fuzzy PID control,and combines it with cascade control to obtain a cascade fuzzy PD-PI control method.Finally,through MATLAB simulation and underwater experiments,the actual effects of PID control and cascade PID control on the heading control and depth control are analyzed,the results show that cascade PID control has faster adjustment speed and better anti-interference ability,it proves that cascade PID control has better control effect in underwater robot control system;the control effect of cascade fuzzy PD-PI control is analyzed,the results show that the method greatly reduces the overshoot in the regulation process on the basis of retaining the strong anti-interference ability of cascade control,it proves the feasibility of the method and show that the dynamic performance of the controller can be improved effectively by using the fuzzy PD-PI control.