Linear Time Varying Control of Unmanned Surface Vehicles

The work resulted in a paper published as

C. Nataraj, and Pritesh Kasliwal, 2005, Intelligent Ships Symposium, May.


This paper considers the path planning control of an unmanned surface vehicle. The nonlinear equations have been derived assuming one control input (rudder). The equations have been written assuming that the ship is moving with a large forward velocity. A steering input has been provided and then the error equations have been derived. The error equations have been linearized assuming small errors; this leads to time varying equations, the control of which is a non-trivial problem. Lyapunov transformations have been applied to change the error equation into a canonical form. A desired closed-loop PD-spectrum and the desired right PD-modal matrix have been chosen and the resulting Sylvester equation has been solved to obtain the parameter matrix. This leads to the closed loop equations for controlling the ship steering of an unmanned ship. Using the kinematic equations and the closed loop control equations the steering motion of the ship has been simulated. An example circular trajectory has been investigated and presented. The control algorithm is shown to be quite effective for tracking of unmanned surface vehicles.