Adaptive barrier function terminal sliding mode control for nonlinear systems subject to uncertain bounded perturbations

This research proposes a tracking control strategy for perturbed and uncertain nonlinear systems by incorporating an adaptive barrier function within a terminal sliding mode control framework. The proposed approach leverages terminal sliding mode control, integrated with the global convergence principle, to ensure global finite-time tracking performance. Additionally, the adaptive barrier function mechanism is employed to effectively mitigate the impact of system perturbations and uncertainties, enhancing overall robustness and stability in nonlinear system control. The key findings and advantages of the proposed method are summarized as: (1) The use of terminal sliding mode control enhances the system’s robustness; (2) Since the controller derivative is continuous except for a discontinuous sign function, integrating the barrier function-based control signal effectively minimizes chattering; (3) By incorporating an adaptive barrier-tuning function, the method ensures robustness against system uncertainties, disturbances, and nonlinearities while mitigating the chattering effect; (4) The proposed method improves tracking accuracy and reduces chattering caused by switching laws; (5) This novel approach holds significant potential for real-world applications, particularly in tracking control scenarios involving input saturations and time delays in uncertain nonlinear systems. Additionally, the proposed approach is highly adaptable for practical applications as it employs two adaptation rules to handle uncertainties and disturbances with unknown upper bounds under specific conditions. Numerical simulation and experimental validation on a rotary inverted pendulum system demonstrate the effectiveness and feasibility of the proposed control scheme for the trajectory tracking control of the real nonlinear system, which confirms the compatibility of the proposed method in real applications.