Estimation of the Dynamic Behavior of a Drum Washing Machine Tub using Multipoint Acceleration Measurements

This study was aimed at predicting the three-dimensional dynamic behavior of the tub in a front-loading (FL) washing machine during the spin-drying process under various unbalanced mass conditions. In FL washing machines, unbalanced mass can induce severe vibration and complex spatial motion. Conventional displacement-based measurement methods suffer from spatial constraints that limit their ability to capture the full tub motion. An experimental approach based on multiple accelerometers mounted on the tub was employed to estimate its rigid-body motion. The estimated displacements were validated against direct measurements obtained from a wire displacement sensor installed on a commercial 25-kg FL washing machine at three unbalanced mass positions (front, center, and rear). The comparison showed that the relative error between the estimated and measured displacements ranged from 3.1 % to 9.3 %, demonstrating high prediction accuracy. Furthermore, the analysis of acceleration signals revealed that as the unbalanced mass becomes more biased toward one side, the spatial motion of the tub exhibits pronounced conical motion characteristics. These results confirmed that the proposed acceleration-based method can reliably estimate the tub’s dynamic behavior while overcoming the spatial limitations of conventional displacement sensor-based techniques to improve both experimental convenience and accuracy.