Automatically characterizing driving activities onboard smart wheelchairs from accelerometer data

Wheelchairs play an important role for people living with locomotor impairments. However, power wheelchair users frequently report both minor and major accidents. The goal of this paper is to advocate for the use of robotic technology, in particular sensor-based detection and automatic classification of activities, to track and characterize activities onboard smart wheelchairs. Experiments were conducted in a clinical setting, in which experienced wheelchair users were asked to conduct a set of typical wheelchair activities. This paper presents an end-to-end pipeline for accurately classifying these activities from accelerometer data using signal processing and machine learning methods. Our classifier achieved an overall accuracy of around 50% in a more than 25 classes classification problem, compared to less than 4% with a random classifier. We also explored the possibility of discovering hidden patterns of activities using unsupervised topic modeling methods. We demonstrated the power of the inferred patterns with two use cases, namely story telling and hazard discovery. Altogether, this work provides new tools for characterizing the usage of smart wheelchairs with typical users.