PendulumTest

PendulumTest is a software framework and methodological toolkit for analyzing pendulum motion and extracting physical parameters such as gravitational acceleration, pendulum length, damping coefficients, and initial phase. The project provides multiple pendulum models, from the ideal simple pendulum to physical pendulums with extended mass distribution, damping, and large-angle corrections, allowing researchers to select appropriate complexity for their data.

Analyses are performed by fitting time-series data of angular displacement to the chosen model. Core algorithms include nonlinear least-squares parameter estimation and, for streaming data, Kalman-filter based processing. The software accommodates measurement errors, outlier handling, and bootstrapping to derive confidence intervals for the estimated parameters.

Typical workflow involves data collection, preprocessing (noise reduction and time synchronization), model selection, parameter estimation, and diagnostic evaluation using residuals and goodness-of-fit metrics. Outputs include parameter estimates with uncertainties, diagnostic plots, and a concise report describing assumptions, fit quality, and potential sources of bias.

PendulumTest is used in physics education laboratories to verify local gravity and effective pendulum length, in metrology and geophysics research to monitor gravity variations, and in engineering contexts for calibration and validation of timing devices relying on pendulum dynamics. It is designed to be platform-agnostic and offers interfaces for Python and MATLAB.

Development and licensing are community-driven, with ongoing contributions from researchers and instructors. The project is distributed under an open-source license and welcomes new models, data formats, and analysis techniques. Users are advised to consider non-ideal effects for large-angle swings and measurement limitations when interpreting results.