3DVidar: A Contact-free 3D Vibration Sensing System Based on a Single mmWave Radar

Vibration sensing is vital for machinery health, which can be used for condition monitoring or anomalies detection. Tra-ditional methods mainly rely on contact-based sensors, which may face deployment challenges. Recently, millimeter wave (mmWave) radar has been regarded as a promising sensing method for vibration monitoring. However, since radar is mainly sensitive to the vibrations perpendicular to its antennas, existing works can only achieve 1D/2D vibration sensing based on single radar, or 3D sensing by multiple ones. In this paper, we propose a contact-free 3D vibration sensing system using single mm Wave radar, called 3DVidar. Considering the insufficient information provided by single radar, we develop a multi-point multi-path signal enhancement method to compensate for the lack of 3D vibration information. Additionally, we design a virtual antenna combination approach to further enrich the information from different perspectives. To reconstruct the 3D vibration trajectory from the complex radar information, we develop a data-driven approach, named TriVFormer, where multi-scale convolution and attention mechanism are employed to effectively fuse the multi-view information. We implement 3DVidar on a commercial mm Wave radar, and the results show that 3DVidar can accurately reconstruct 3D trajectory across various distances and angles, with mean error of 0.4526Hz and 0.0202mm, respectively.