Saturation based nonlinear PID control for underwater vehicles: Design, stability analysis and experiments

Abstract

During sea missions, underwater vehicles are often exposed to changes in the parameters of their control systems and subject to external disturbances due to the influences of ocean currents. These issues make the design of a robust controller quite a challenging task. This paper focuses on the design of a nonlinear PID controller, based on a set of saturation functions for trajectory tracking on an underwater vehicle. The main feature of the proposed control law is that it preserves the advantages of robust control and remains easy to fine-tune in real applications. Using the Lyapunov concept, we prove the asymptotic stability of the closed-loop tracking system. The effectiveness and robustness of our proposed controller for trajectory tracking in depth and yaw dynamics is demonstrated through real-time experiments.

Adaptive disturbance observer for trajectory tracking control of underwater vehicles

“…Remark 6. It is worth to notice that in this manuscript is different from the work presented in [19]. On one hand, in study [19], a nonlinear PID was proposed while in this work, we propose the improvement of the nonlinear PD proposed by [18].…”

“…However, it is well-known that the performance of the PD/PID controller is degraded when the plant is highly nonlinear or time-varying. To overcome these drawbacks, the PD/PID controllers are improved adopting strategies based on auto-adjustable [15], saturated [16], adaptive [17], or nonlinear functions [18,19]. For instance, a nonlinear PID for the trajectory tracking of an AUV is proposed in Guerrero et al [19].…”

“…To overcome these drawbacks, the PD/PID controllers are improved adopting strategies based on auto-adjustable [15], saturated [16], adaptive [17], or nonlinear functions [18,19]. For instance, a nonlinear PID for the trajectory tracking of an AUV is proposed in Guerrero et al [19]. In this work, a PID was saturated by a whole set of nonlinear functions in order to provide robustness towards external disturbances and parametric uncertainties.…”

“…On one hand, in study [19], a nonlinear PID was proposed while in this work, we propose the improvement of the nonlinear PD proposed by [18]. On the other hand, in this manuscript, we use sliding mode theory to improve a PD controller while in work [19] is an extension of the saturated based-control.…”

Robust Adaptive Tracking Control of Underwater Vehicles: Design, Stability Analysis, and Experiments

“…As a consequence, the design of a tracking control scheme for the such vehicles becomes a critical issue [9]. Indeed, several control schemes have been proposed in the literature to address this problem, such as improved control schemes based on PD and PID control [10] [11] [12], robust control [13], adaptive control [14], intelligent and hybrid control [15].…”