This paper proposes a global sliding mode observer for a class of nonlinear mechanical systems with two degrees of freedom. For the observer design, besides the usual Coriolis and centrifugal forces, we consider (discontinuous) dry and viscous friction and non vanishing uncertainties/perturbations. Moreover, the system is not required to be bounded-input-bounded-state, rendering the observer design problem challenging. For this class of systems, a dissipativity-based sliding-mode observer, with theoretically exact global finite-time convergence to the actual velocities, is proposed. To illustrate the effectiveness of the proposed observer, experimental results on a cart-pendulum system are presented.

中文翻译：

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一些不确定机械系统的全局滑模观测器

本文提出了一类具有两个自由度的非线性机械系统的全局滑模观测器。对于观测器设计，除了通常的科里奥利力和离心力之外，我们还考虑（不连续的）干燥和粘性摩擦以及非消失的不确定性/扰动。此外，系统不需要是有界输入有界状态，这使得观察者设计问题具有挑战性。对于这类系统，提出了一种基于耗散率的滑模观测器，理论上可以精确地全局有限时间收敛到实际速度。为了说明所提出的观察器的有效性，展示了推车钟摆系统的实验结果。