Adaptive Second-Order Sliding Mode Control Design With Autonomous Agricultural Vehicle Application

The objective of this article is to investigate the adaptive second-order sliding mode (SOSM) control design for nonlinear dynamical systems which can achieve high-precision adaptive estimation of system uncertainties. An adaptive SOSM control strategy based on the immersion and invariance (I&I) technique is proposed, which breaks away from the conventional approach that relies on the certainty equivalence (CE) principle. It can indirectly estimate the inherent uncertainties within the system, thereby ensuring a high degree of estimation precision. The proposed control strategy is shown to be capable of handling a class of uncertain nonlinear systems with mismatched terms, which overcomes the limitation of traditional adaptive SOSM control strategies that are typically restricted to systems with matched terms. Furthermore, a rigorous Lyapunov analysis is conducted to confirm the finite-time stability of the closed-loop control system. Finally, the proposed control strategy is applied to an autonomous agricultural vehicle (AAV) to demonstrate its practicality in engineering applications.