In this paper, the robust stabilization problem by means of quantized sampled-data event-based (QSE) controllers is investigated for nonlinear systems affected by state delays and unknown disturbances. In particular, a methodology for the design of robust QSE stabilizers is provided for control-affine nonlinear systems affected by unknown actuation disturbances and unknown measurement errors. Firstly, the notion of Steepest Descent Feedback (SDF), continuous or not, is suitably revised in order to deal with the robustification of event-based controllers. Then, Input-to-State Stability (ISS) redesign methodologies are used to provide the robustification term which is added to the SDF at hand in order to arbitrarily attenuate the effects of unknown external disturbances affecting the considered control scheme. A spline approximation approach is used in order to cope with the problem of the possible non-availability in the buffer of suitable past values of the system state required for the correct application of the proposed robust QSE controller. It is proved that there exist a suitably fast sampling and an accurate quantization of the input/output channels such that: the robust QSE implementation of SDFs, continuous or not, ensures the semi-global practical stability of the related closed-loop system, regardless of the above disturbances, provided that the observation errors affects marginally the new added control term. The stabilization in the sample-and-hold sense theory is used as a tool to prove the results. The provided results include the case of non-uniform quantization of the input/output channels and the case of aperiodic sampling. Applications are presented in order to validate the results.

中文翻译：

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非线性时滞系统数字事件稳定器的鲁棒性研究

在本文中，针对受状态延迟和未知扰动影响的非线性系统，研究了基于量化采样数据事件（QSE）控制器的鲁棒稳定性问题。特别是，为受未知驱动扰动和未知测量误差影响的控制仿射非线性系统提供了鲁棒QSE稳定器的设计方法。首先，对连续或非连续的最速下降反馈（SDF）的概念进行适当修改，以处理基于事件的控制器的鲁棒性。然后，使用输入状态稳定性 (ISS) 重新设计方法来提供鲁棒性项，将其添加到手头的 SDF 中，以便任意减弱影响所考虑的控制方案的未知外部干扰的影响。使用样条近似方法来解决缓冲器中可能无法获得正确应用所提出的鲁棒QSE控制器所需的系统状态的合适过去值的问题。证明存在输入/输出通道的适当快速采样和精确量化，使得：无论连续与否，SDF的鲁棒QSE实现都能确保相关闭环系统的半全局实际稳定性，无论上述干扰的影响，前提是观测误差对新添加的控制项影响很小。采样保持传感理论中的稳定性被用作证明结果的工具。提供的结果包括输入/​​输出通道的非均匀量化的情况和非周期采样的情况。提出应用程序是为了验证结果。