Effect of Dynamic Stability Derivatives Coefficients on the Design of Operational Parameters of the Actuator in an Underwater Robot

Determining a dynamic model for an underwater robot is of great importance in design of guidance and control system. Researchers always need a complete knowledge about hydrodynamic stability derivatives coefficients of vehicle with sufficient accuracy to design a successful control system for underwater vehicles. The selection of proper actuator in control system is important on the global performance of the system and the costs of the project. Usually, the effect of dynamic stability derivative coefficients is not considered in the design of actuators; therefore, in the present study, it is tried to investigate the effect of these coefficients in the design of actuators. For this purpose, firstly, the equations of motion for an underwater robot are presented. Then, hydrodynamic coefficients that contains static and dynamic coefficients are determined, using a rapid computational code and, then, the effect of hydrodynamic stability derivatives coefficients on the operational dynamic parameters of vehicle such as the bandwidth of the system dynamics and its role in the control system are considered. Finally, the selection of appropriate actuator for the underwater robot and the effects of natural frequency of actuators on the system performance are studied.