Stability prediction is a key step to implement a real-time hybrid simulation (RTHS) testing successfully. There are two kinds of stability prediction methods based on continuous and discrete transfer function. In the family of continuous transfer function based methods, the numerical and physical substructures are seen as continuous systems together with loading system. In discrete family, all subsystems in RTHS are regarded as discrete systems. Actually, in a real RTHS, the numerical substructure is discrete; the physical substructure is continuous. Meanwhile, the signal coordination is needed to balance the sampling interval between numerical solution and physical loading, which is ignored in the reported methods. In order to predict the stability of RTHS system more accurately, this work develops a discrete-continuous stability analysis method through the concept of gain margin, which can consider the performance of numerical substructure, physical substructure, loading system and signal coordination comprehensively. And the accuracy of the method is verified by SIMULINK simulation and experimental testing. Based on shaking table and actuator RTHS systems, the performance of continuous and discrete methods is compared with the proposed method analytically. The results show that the discrete method and continuous method have slight influence on the stability prediction with a small integration step (e.g 1 ms). However, with the increase of integration step, compared with the discrete-continuous method, the discrete method and continuous method may overestimate or underestimate the stability of a real RTHS system.

稳定性预测是成功实施实时混合仿真 (RTHS) 测试的关键步骤。基于连续和离散传递函数的稳定性预测方法有两种。在基于连续传递函数的方法系列中，数值和物理子结构与加载系统一起被视为连续系统。在离散族中，RTHS 中的所有子系统都被视为离散系统。实际上，在真正的 RTHS 中，数值子结构是离散的；物理子结构是连续的。同时，需要信号协调来平衡数值解和物理加载之间的采样间隔，这在报告的方法中被忽略。为了更准确地预测 RTHS 系统的稳定性，本工作通过增益裕度的概念发展了一种离散-连续稳定性分析方法，可以综合考虑数值子结构、物理子结构、加载系统和信号协调的性能。并通过SIMULINK仿真和实验测试验证了该方法的准确性。基于振动台和执行器 RTHS 系统，连续和离散方法的性能与所提出的方法进行了分析比较。结果表明，离散法和连续法对小积分步长（如1 ms）稳定性预测的影响很小。然而，随着积分步长的增加，与离散-连续法相比，离散法和连续法可能会高估或低估真实RTHS系统的稳定性。