Trajectory Tracking Controllers for AUVS: An Integrated Approach to Guidance and Control System Design

Abstract

This paper describes a solution to the problem of 3-D trajectory tracking for Autonomous Underwater Vehicles (AUVs). The trajectories considered consist of segments of trimming helices, which are parameterized by the vehicle's linear speed, yaw rate and flight path angle. Motivated by recent developments in robotics, the linear position of an AUV is given in terms of its location with respect to the closest point on a desired trajectory, together with the length of an imaginary curve traced along that trajectory. Tracking of a trimming trajectory by the vehicle at a fixed speed is then converted into the problem of driving a generalized error vector - that implicitly includes the distance to the trajectory - to zero. By showing that the linearization of the generalized error dynamics about trimming trajectories is time-invariant, the problem of trajectory tracking is posed and solved in the framework of gain scheduled control theory. This leads to a new method for the integrated design of guidance and control systems for AUVs.