This paper proposes an unknown input observer for nonlinear systems with input decoupling via system invertibility. Starting from a suitable reformulation of the model of a generic nonlinear system, obtained by merging all system uncertainties with respect to an appropriate nominal linear model into a disturbance vector, the proposed observer can asymptotically copy both the system state and unknown inputs, even in the presence of measurement noise. Formal proof of the estimate convergence is demonstrated analytically. A comparison of the proposed method with existing solutions is shown in simulation, and the method’s effectiveness in real-world scenarios is demonstrated by experimental results on a soft articulated robot.

中文翻译：

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非线性动态模型的线性未知输入状态观测器

本文提出了一种非线性系统的未知输入观测器，通过系统可逆性进行输入解耦。从通用非线性系统模型的适当重构开始，通过将适当的标称线性模型的所有系统不确定性合并到扰动向量中获得，所提出的观测器可以渐近地复制系统状态和未知输入，即使在存在测量噪声。通过分析证明了估计收敛性的形式证明。仿真中显示了所提出的方法与现有解决方案的比较，并且软关节机器人上的实验结果证明了该方法在现实场景中的有效性。