Abstract
In this paper, we propose a method of sitting posture classification with chair-shaped device, called SenseCaster, which non-intrusively measures a user's center of pressure and weight using a pressure sensor embedded inside caster. We also propose a method of estimating a seat rotation with neodymium magnet and magnetic sensors to calculate the center of pressure. We implemented and conducted several experiments to confirm SenseCaster’s functionality. In the first experiment, we evaluate an accuracy of measuring a user’s center of pressure and weight. The mean absolute error was (2.7, 3.3) mm and 0.31 kg, and repeatability error was (1.3, 1.8) mm and 0.10 kg. In the second experiment, we classified ten simple sitting postures using the center of pressure and the weight data of 14 subjects. The average accuracy was 0.80 for familiar users (SenseCaster had collected their data before) and 0.70 for unfamiliar users.
