Research on Ultra-Sensitive Omnidirectional Strain Sensor Array for Human Motion Detections

Human body movements are flexible and multidirectional. To obtain more accurate parameters during human motion monitoring and health managing, ultra-sensitive and omnidirectional sensing equipment is needed. Therefore, an ultra-sensitive omnidirectional strain sensor array, which utilizes a bionic spider crack sensing mechanism, is proposed and designed to detect the multidirectional mechanical strains over the skin generated by human activities. Holding the mechanism of the bionic crack sensing layer as foundation, the bionic crack strain sensor exhibits an ultrahigh strain sensitivity of GF =1 920 031. The proposed omnidirectional strain sensor array consists of three bionic crack strain sensors spaced 120° apart. This configuration enables the array to acquire and distinguish mechanical strains from any direction within its coverage skin area. The sensor array can be attached to the skin firmly to measure skin deformation caused by joint and muscles’ activity, as well as the angle of the wrist movements. The monitoring data obtained by the fabricated sensor array was used to train and test a badminton swing action recognition model, and eight types of badminton swing actions were successfully identified with an overall accuracy of 98.125%. This demonstrates that the omnidirectional strain sensor array can provide high-precision human motion posture information for intelligent health management and medical limb monitoring.