Development of a wearable modular IMU sensor network suit with a distributed vibrotactile feedback for on-line movement guidance

This paper describes the fabrication of a modular wireless IMU sensor network suit with a distributed vibrotactile motor for body postural measurements with feedback. Each sensor measures the absolute orientations then transmits them into one portable hub. The module can be connected with up to four vibration motors to provide feedback to the user. Each vibration motor is hosted by a block sliding through the elastic strap used for attaching the module. The vibration motors on the strap can be positioned to different sides of the body to indicate movement directions. The suit is used to train and evaluate various static and dynamic tasks. The distribution of vibrotactile feedback targets particular features of movement in real-time such as amplitude and velocity. Preliminary experiments show the ability to identify normal walking and limping based on metrics such as the trajectory of the center of mass, the energy of left and right legs, and the calf and thigh angles to the vertical. Online identification of gait is the primary key to trigger a wearable assistive device.