Simulation-Based Inference for the Amortized Determination of Physical Model Parameters of a Mechanical System for Diagnostics and Prognostics

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Published Jul 3, 2026
Cedric Schenkel Kai Hencken

Abstract

Many diagnostic and prognostic applications rely on complex measurements, including time series and high-dimensional
data. In a common approach, one extracts key features that capture the system degradation while ignoring nuisance effects. Physical system properties are of interest due to their (direct) relation and relevance to degradation and failure modes, often allowing for superior interpretability compared to purely data-driven approaches. However, determining them
from the observed data is difficult due to the inherent non-identifiability in already rather simple models. Recently developed simulation-based inference (SBI) approaches, based on neural posterior estimates (NPE) and conditional invertible neural networks (cINN), allow the incorporation of domain knowledge in the form of simulation capabilities to extract model parameters as physics-based features for diagnostics and prognostics. This is demonstrated in the case of a mechanical actuator that operates medium voltage breakers. Simulations of a simplified multi-body model are used as input for the training of a cINN that not only provides a set of physical parameter values but also their respective uncertainties. By using simulated data as synthetic measurements and
conducting a number of statistical checks, the performance of the trained cINN is confirmed. We demonstrate that accurate multi-body parameter estimation is possible for some parameters, whereas those that cannot be identified from either the
opening or closing motion remain distributed according to the prior distribution, without significantly affecting the others.
We further show that the opening and closing motions are sensitive to different parameters, complementing each other
in this respect. Data from a real mechanical endurance test are used to demonstrate the method’s effectiveness in a real-
world application. Its integration into a diagnostics or prognostics framework is discussed as an outlook.

How to Cite

Schenkel, C., & Hencken, K. (2026). Simulation-Based Inference for the Amortized Determination of Physical Model Parameters of a Mechanical System for Diagnostics and Prognostics. PHM Society European Conference, 9(1), 1–10. https://doi.org/10.36001/phme.2026.v9i1.5040
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Keywords

simulation-based inference, physics-based diagnostics, multi-body mechanical model, parameter estimation, Bayesian inference, neural-posterior estimate, Bayesian workflow

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Technical Papers