Control and modeling of underwater flexible manipulator structure

Abstract

The use of flexible structures in many engineering applications is expanding rapidly. Position control is delicate, such as angular position control of a flexible structure especially underwater condition. Flexible structure in an underwater condition often having the problem of the hub angle position as the hub angle is affected by the inline force of the flexible structure underwater. To develop an optimum control system for the horizontal motion of such condition, the operating system must first be identified. A system model of an experimental test rig representing the Underwater Flexible Single Link Manipulator System (UFSLMS), needs to be developed before designing a controller to control the hub angle position. The objectives of this project are to identify the model and develop the controller to control the hub angle position of a UFSLMS. Previous studies have shown that parametric modelling involving Auto Regressive with Exogenous Input model using Recursive Least Squares algorithm, and non-parametric modelling involving Evolution Algorithm are suitable to model the UFSLMS system, with acceptably low Mean Square Error. The project is done by reviewing the UFSLMS dynamic modelling and control methodology. The collection of data from the UFSLMS system will be simulated and identified as the dynamic UFSLMS. A Proportional- Integral-Derivative controller is developed based on the system identification model, using heuristic techniques within MATLAB environment and robustness test is carried out at different magnitudes to determine the robustness of the controller. The performance of the controllers thus developed is verified and validated by simulation on MATLAB SIMULINK. The objectives are achieved when the controller is proven to be stable by effectively control the hub angle position in the horizontal motion underwater.