Abstract: To address the challenge of achieving high-precision tracking in a ball and plate system subject to uncertain distur-bances such as external loads,friction,and cross-coupling interference,this paper proposes an enhanced approach that combines an improved nonlinear disturbance observer(NDO) and a nonlinear information gain sliding mode control strategy.Utilizing error transformation techniques based on a prescribed performance function(PPF),we constrain the error within specified bounds,and introduce the improved NDO to estimate the uncertain disturbances accurately.We leverage the precise estimation to design a sliding mode controller with a corrective term on the sliding surface,which can reduce the impact of disturbances,and enhance control precision.Furthermore,we employ nonlinear information gain to adaptively adjust the switching gain,so as to mitigate chattering effects.Simulation results demonstrate that the enhanced NDO effectively estimates disturbances,leading to improved dynamic performance.The proposed control approach exhibits higher control precision and disturbance rejection capabilities.

Key words: Ball and plate system, Prescribed performance function, Nonlinear disturbance observer, Uncertain disturbances, Sliding mode controller