Research On The Three-dimensional Trajectory Tracking Of Underactuated Autonomous Underwater Vehicle

Autonomous Underwater Vehicle (AUV) has played an important role in the seaexploration. Underactuated AUV has a system with high nonlinear motion andun-integrality, while there are input constraints. So the research on AUV has a tightcompact on the actual motion of AUV. Based on this question, this paper does someresearches on the stabilization and trajectory tracking of AUV.At first, the forces on the AUV are analyzed to gain the kinematic and dynamicmodels. Based on the models, the un-integrality and controllability of movement systemare analyzed while the physical restriction of AUV is studied. The analysis beyondindicates there are control laws which are time-variable to make foundation for thestabilization and trajectory tracking of AUV.The stabilization of underactuated AUV is designed in two-dimensional motion andthree-dimensional motion. The aim of stabilization is to stabilize the AUV from anyinitial position to the balance point with proper inputs. Based on differentialhomeomorphism, the planar kinematic and dynamic equations of AUV are transferred toa cascaded system. The simple controller is gained with Lyapunov function and provedby differential theory. Based on quaternion theory, the six degree equations aresimplified and the controller is gained by virtual inputs.The trajectory tracking of underactuated AUV is designed in two-dimensionalmotion and three-dimensional motion. The aim of trajectory tracking is to design acontroller to propel the AUV advance along the designed trace. Compared withstabilization, trajectory tracking is to stabilize the error equations which are difficult toacquire. With the assumption of virtual AUV’s motion equations, the planar errorequations are acquired which are transferred to cascaded systems based on differentialhomeomorphism. The controller is gained by the theory of Lyapunov function andbackstepping. The difficult of three-dimensional trajectory tracking owes to theinter-action of the motions. In spite of the motion of roll, the cascaded systems ofstraight line tracking error equations are gained through the designed angles of yaw andpitch, and the controller is gained by Lyapunov function. In the curve trajectory trace, the controller is gained by the actuated equations while using linear theory to analyze virtualinputs. All the controllers are simulated in the Matlab/Simulink, which prove that thecontrollers are effective and have a good controlling performance.After the control law is gained, which means the force and torque are gained, how tofeedback them to the propeller’s rev and the angle of vertical rudder and planar wing arediscussed by analyzing the trust distribution of the three-dimensional straight-linetrajectory tracking.