According to the literature, structural health monitoring techniques based on state observers usually evaluate the differences between measured and estimated states to detect a damage. The practical application of this strategy is an unfeasible solution if the monitoring system needs to detect damages in a region of the structure where sensors cannot be placed. For these cases, a common alternative is to use sensors at nearby regions, but the accuracy of detection can be reduced. In this context, the present article introduces a new approach for damage detection in mechanical systems using the relative difference obtained from the estimations of a state measured by two different sensors. In this method, the estimated state is obtained by sensors in different positions from the one that needs to be monitored. To do so, parallel full-order state observers are employed and an optimal gain is computed. An index is proposed to detect the damages, which is time-dependent and computed using the responses of the systems. Numerical simulations are carried out considering two different mechanical systems. Linear and nonlinear damages are considered, and the results demonstrate that the proposed approach can detect damages accurately.

根据文献，基于状态观察器的结构健康监测技术通常评估测量状态和估计状态之间的差异以检测损坏。如果监控系统需要检测无法放置传感器的结构区域中的损坏，则该策略的实际应用是一种不可行的解决方案。对于这些情况，常见的替代方法是在附近区域使用传感器，但会降低检测的准确性。在这种情况下，本文介绍了一种使用从两个不同传感器测量的状态估计中获得的相对差异来检测机械系统中损坏的新方法。在这种方法中，估计状态是由与需要监控的位置不同的传感器获得的。为此，采用并行全阶状态观察器并计算最佳增益。提出了一个指标来检测损坏，该指标与时间相关并使用系统的响应进行计算。考虑两种不同的机械系统进行数值模拟。考虑了线性和非线性损伤，结果表明所提出的方法可以准确地检测损伤。