Trajectory Tracking Control Of Underactuated Surface Vessels With Rolling Constraints

As small intelligent surface movement platform with fast and flexible characteristics, surface vessels play important roles in scout, remove mines, rescue, hydrological investigation when they execute military and civil missions. Generally, surface vessels are underactuated, since they control horizontal transverse, longitudinal position and yaw three degree of freedom motion by propeller propulsion and rudder steering torque. The surface vessels often deviate from the intended safety track with interference of wind, wave and flow, as well as having a larger roll,which affects comfort of occupants, damage goods, and even overturn. So it is a hot issue in the field of vessels controlling in recent years that improving maneuverability to overcome roll and realize trajectory tracking control.In this paper, the finite time control is used to study the underactuated surface vessels trajectory tracking control problem of three degree of freedom. In order to avoid the danger caused by the violent rolling, a four degree of freedom trajectory tracking model is adopted,which is based on the predictive control algorithm. The roll angle is used as the state constraint,and the predictive controller is designed to control the course. At the same time, noise is eliminated by using the Sage-Husa adaptive Kalman filtering technique, and the disturbance observer is designed to eliminate disturbance, which achieve the purpose of trajectory tracking and anti sway.Firstly, base on three degree of freedom trajectory tracking control model, Backstepping nonlinear control law is elaborated so that surface vessel can quickly track predetermined trajectory and ensure the stability of closed loop system. Considering the influence of wind,wave and flow, Backstepping and finite time control integrated control law is designed to improve the robustness of surface vessels trajectory tracking system for fast convergence and strong anti-interference ability of finite time control. They are not only proved in theoretically,but also verified by the simulation.Moreover, considering roll by the influence of wind, wave and flow, trajectory tracking of underactuated surface vessels is studied by the design of predictive controller with the constraint of roll angle in four degree of freedom linear model coupled with roll, as well as used for predictive model, roll optimization and feedback correction. In simulation, different predictionsteps and different weighting matrices are changed to adjust prediction states real time. It is verified that predictive controller can reduce the influence of rolling. The states of system can converge to the equilibrium point and reach a steady state, and ultimately surface vessels can sail safely on a predetermined trajectory.At last, in view of heading angle is only measurement value of surface vessels trajectory tracking system, while rest of states are estimated, Sage-Husa adaptive Kalman filtering technique is used to estimate optimal states for influence of system noise and measurement noise.Aiming at disturbances of wind, wave and flow, disturbance observer is designed to estimate interference and compensate real-time in predictive control. The predictive control of surface vessels trajectory tracking is synthetically analysed with noise, interference and rolling constraint.