Trifilar Pendulum - Mass Moment of Inertia Measurement

This repository contains the complete design files, software, and experimental data associated with a low-cost trifilar pendulum system for measuring the mass moment of inertia (MoI) of small objects. The system was developed primarily for CubeSat-scale payloads, but is applicable to other rigid bodies such as drone components and small mechanical assemblies.

The dataset supports the validation of the measurement system and consists of recorded video data, processed measurement outputs, and calibration results. Measurements were performed using objects with analytically known inertia properties, enabling direct comparison between measured and theoretical MoI values. The dataset includes multiple test configurations designed to evaluate the influence of key experimental parameters, including camera type, frame rate, camera distance, and suspension configuration.

Data acquisition was carried out by recording the oscillatory motion of a trifilar pendulum platform using a fixed camera positioned below the test article. Printed n-fold edge markers were attached to the platform to enable automated tracking. The provided Python-based software processes the recorded video to extract the oscillation period and compute the corresponding MoI using standard trifilar pendulum relations. For each configuration, multiple repeated measurements were performed, and the dataset includes both individual trial results and aggregated statistics.

The data demonstrates that the system provides reliable MoI measurements for moderate and high inertia values, with increasing measurement error observed at lower inertia levels due to reduced sensitivity and greater influence of experimental disturbances. The dataset also illustrates the impact of imaging conditions and suspension characteristics on tracking performance and measurement accuracy.

All files are structured to allow full reproducibility of the experimental setup, including hardware fabrication, data acquisition, and post-processing. The repository can be used to replicate the validation results, assess alternative tracking approaches, or adapt the system for related applications in spacecraft testing, robotics, and laboratory-scale dynamics experiments.