PATH-FOLLOWING CONTROL FOR UNDER-ACTUATED AUTONOMOUS SURFACE VEHICLES BASED ON NONLINEAR MODEL PREDICTIVE CONTROL

Abstract

Path-following control is one of the most important problems in controlling autonomous water vehicles because it has many practical applications.
Compared with vehicles moving on the ground, controlling autonomous water vehicles to follow a trajectory becomes much more difficult, especially with
vehicles that are under-actuated. To control a vehicle to follow a path, it is necessary to design a guidance law and a control law. The guidance law is
responsible for determining reference values, such as position and velocity. The control law designs the force to control the vehicle to the reference value,
thereby converging to the desired trajectory. Most water vehicles often have lateral underactuation, which makes the trajectory tracking control problem
more difficult. To solve this problem, in the article, the authors change the control point and redefine the dynamic model for this new control point. The
article also introduces the guidance law and provides proof to ensure that the vehicle converges to the desired trajectory. The force controller is built based
on Nonlinear Model Predictive Control technique, taking into account the control input constraints. Simulation results performed on Matlab demonstrate
the effectiveness of the proposed method.