Research On Identification And Control Of Open-frame AUV

With the increase of ocean research, more and more researchers apply themselves to the development of autonomous underwater vehicle (AUV) which is an important tool in the accomplishment of many special missions. As a vehicle which works in complicated oceanic environment, autonomy and security are the basis for AUV. Intelligent control is a key technology to complete the autonomous control and the task of AUV. Essential characteristic of AUV which is understood completely and intelligence of AUV which is improved are crucial to the study and the application.The paper presents a dynamical model of the "Beaver" open-frame underwater vehicle which is developed independently in the Underwater Vehicle Intelligent Control Technology Lab, describes identification methodologys for the underwater vehicle and studies the motion control technique of the vehicle.Based on analyzing the kinematics and the dynamics effecting an AUV, a dynamics model of 6 degrees of freedom (DOF) is established. A simplified model is obtained aiming at an open-frame structure and design characteristics. A dynamic experiment is used for the identification of dynamics model of the thrusters, which is carried out in a water tank. How to identify model parameters via a least squares technique is studied in this paper. Because the parameters of dynamical model are variable during AUV working, a stable adaptive technique as an online identification method is proposed. Experiments using "Beaver" AUV show that the stable adaptive online identification method is feasible.After constructing the dynamical model and the simulative environment of the vehicle, an adaptive nonlinear model-based controller for AUV is designed to track both position and velocity trajectories. Some experiments with "Beaver" AUV are done. The performance of the controller is good in these experiments.