Initial study of body seat interface measurement parameters

This paper introduces a potential seating comfort measurement system based on integrating force, temperature and relative humidity information. Placement of the sensors was consistent with our previously published data, with temperature and humidity sensors placed under each thigh (2 of each sensors) and the coccyx (1 of each sensor) while force sensors (4) were located under each thigh and each ischial tuberosity. Before the in situ trials were initiated, the force, temperature and humidity sensors were assessed for variance in output. The sensors performed consistently with standard deviations (SDs) of: temperature sensor ± 0.2 ºC; humidity sensor ± 0.3 %; force sensor (voltage output: ranging from 3.67 V to 4.31 V as loading forces changing from 5 kg to 15 kg) ± 0.09V. In the twenty-minute in situ experiments, ten participants sat on each of the following surfaces in turn over a three-day period, foam, wood and moulded foam cushions. A Latin square design was used to reduce any order effect regarding the order of seating surface. Sitting posture adjustment time, maximum temperature and mean relative humidity were recorded along with the comfort score questionnaire to evaluate the relationship between objective parameters and the perceived seating comfort. The experimental results suggest aspects of the raw data from these sensors and changes in these parameters might be used to relate to comfort.