A discrete-time terminal sliding mode controller design for an autonomous underwater vehicle

Abstract

Autonomous underwater vehicle (AUV) are underwater robotic devices intended to explore hostiles territories in underwater domain. AUVs research gaining popularity among underwater research community because of its extensive applications and challenges to overcome unpredictable ocean behavior. The aim of this paper is to design discrete time terminal sliding mode control (DTSMC) reaching law-based employed to NPS AUV II purposely to improve the dynamic response of the closed loop system. This is accomplished by introducing a nonlinear component to sliding surface design in which the system state accelerated, and chattering effect is suppressed. The nonlinear component consist of fractional power is to ensure steeper slope of the sliding surface in the vicinity of the equilibrium point which lead to quicker convergence speed. Thus, the chattering effect in the control action suppressed as the convergence of the system state accelerated. The stability of the control system is proven by using Sarpturk analysis and the performance of the DTSMC is demonstrated through simulation study. The performance of DTSMC is benchmarked with DSMC and PID controller

Heading control of an autonomous underwater robot with sliding mode and backstepping techniques

“…The importance of sliding mode controllers lies in: high precision, fast dynamic response, stability, simplicity of design and implementation, and robustness in the face of any variation of internal or external parameters [17], [18]. All these positive aspects of sliding mode control should not mask certain disadvantages [19]- [21]. The sliding mode controls proceed discontinuously, which leads to exciting all the frequencies of the system to be controlled, and therefore modes are not necessarily taken into account in modeling.…”

The taxi function

“…There are a multitude of papers about this topic. Here we cite some of them as example [1]- [5]. This work is conncerned about these topics, specifically about lane keeping control and lateral control.…”

“…TRAJECTORY WHERE ALL ROUTES ARE STRAIGHT AND PERPENDICULAR Definition 1 Given an arbitrary function f defined in [a, b] and let P s = {x 0 = a, x 1 , ..., x s = b} be a partition, we define the RAFU Method on approximation to the function function f to all approximation procedure that uses functions C n defined in [a, b] to approach the function f where the functions C n (x) are defined by (1).…”