Backstepping Control-based Trajectory Tracking for Tail-actuated Robotic Fish

Abstract

In this work, we propose a backstepping-based trajectory tracking control approach for a tail-actuated robotic fish, which has highly nonlinear and under-actuated dynamics. A modified heading error is introduced that augments the heading error with a term dependent on lateral tracking error, which enables the exploitation of dynamics coupling to address the under-actuation challenge and stabilize both the heading and lateral tracking errors. Furthermore, the input constraints imposed by physical limitations are accounted for with the incorporation of an auxiliary system. Simulation results support the efficacy of the proposed control approach and its advantages are shown via comparison with a PI controller.