Peak-Free Feedback-Cascaded Generalized Extended High-Gain Observer: A Multisaturation Approach
提出一种新型扩展高增益观测器，通过广义化、反馈级联和多饱和技术，在提高估计精度的同时消除瞬态峰值，并简化数值实现。
This article proposes a novel extended high-gain observer (EHGO). First, we generalize the standard EHGO by augmenting it with an <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</i>-order chained integrator, forming the generalized EHGO (GEHGO). This generalization significantly enhances estimation accuracy for both system states and total disturbance. To address the numerical issues arising from the high-gain parameter raised to power <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">n</i> + <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</i>, we employ a feedback-cascaded technique. This reconfigures the generalized observer into a series of feedback-cascaded second-order high-gain observers (HGOs), crucially reducing the high-gain exponent to just two and greatly simplifying numerical implementation. Meanwhile, two saturation nonlinearities with suitable thresholds are embedded in each second-order HGO to prevent the peaks of the transient estimates. The global convergence of this novel EHGO is rigorously demonstrated using Lyapunov-based arguments. We also address the issue of sensitivity to high-frequency measurement noise and demonstrate that <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">m</i> needs to be constrained to preserve robustness. Finally, numerical simulations illustrate the obtained theoretical results.