Robust PIλ controller design for AUV motion control with guaranteed frequency and time domain behaviour

Abstract

Autonomous underwater vehicles require a motion control system for performing underwater tasks such as exploring and developing marine resources. This study proposes a fractional-order proportional-integral ( P I λ ) controller for autonomous underwater vehicles motion control that simultaneously guarantees frequency and time domain behaviour. First, a stabilisation process is presented for the controlled system, and a three-dimensional stable surface is obtained. Subsequently, the controller parameters can be tuned. Then, to guarantee frequency and time domain control performance simultaneously, the frequency domain behaviour is studied through a modified flat phase property, and the time domain behaviour is improved through parameter optimisation. The set-point regulation and noise suppression performances of the autonomous underwater vehicles motion control system indicate that the proposed P I λ controller provides more flexibility in improving the system's robustness and transient performance.