Adaptive second-order sliding mode control with barrier functions for uncertain dynamic systems: design and experimental validation

The primary contribution of this paper is the development of a novel finite-time control method that can track a reference signal in the presence of both matched and unmatched external disturbances with unknown upper bounds. Initially, a second-order sliding mode control with an integral component is designed to ensure finite-time stability. This control is referred to as Second-Order Integral Sliding Mode Control, where a Proportional–Integral–Derivative (PID) sliding surface is defined and filtered to mitigate chattering, resulting in second-order sliding mode control. To eliminate reliance on the upper bounds of disturbances, an adaptive law is applied, which increases the control gain until the tracking trajectories reach a neighbourhood of the PID sliding surface in the finite time. A positive semi-definite barrier function is then introduced to reduce the convergence region and maintain the tracking error state within that region. Finally, an electromechanical throttle experiment is conducted to validate the proposed control method, demonstrating good performance. In addition, we compare our control method's performance to the standard integral sliding mode control, showing that our approach demonstrates superior performance