Stretchable Sensor Network

Over the years, we have witnessed the explosive growth of autonomous vehicles, smart buildings and intelligent robots. The three emerging areas embrace a common domain, smart structures, which have been developed both intensively and extensively at a tremendous speed in the last two decades. The evolution of smart structures has brought higher requirements and more challenges to structural health monitoring (SHM) territory with the target of realizing automated SHM-support systems for unmanned structures. As the prerequisite to empower a structure with smartness, sensor networks mimic the tactile sensing and sensory nerves of a human being and are responsible for data acquisition and data transmission. Skin-like sensor networks are either embedded in or attached to the system containing central control and command unit — the “brain” will then process the information and determine the actions. Finally, appropriate decisions and associate instructions are transmitted back to the structure and executed by the actuators, simulating the human motor nerves and the innervated muscle fibers.

Structures and Composites Laboratory (SACL) at Stanford University has been continuously devoting to the development of bio-inspired stretchable sensor networks, which consist of two main components, the sensor node with a square electrode as the substrate for electrical conduction and the stretchable wire which has a serpentine structure to enable different stretchabilities. Multiple research works have been done based on this core concept, including thermal sensors, impact sensors, pressure sensors and stretch ratios ranging from 1:7 up to 1:100. This fabrication-expansion-integration all-in-one process has three major advantages over the traditional approach. Firstly, it greatly simplifies the sensor mounting method which requires experienced technicians to individually install each sensor by hand. Secondly, it replaces the messy long wires and complicated cabling with orderly short interconnects. Thirdly, it reduces the footprint of the sensors to maintain high sensing resolution and minimize parasitic effects on the host structure. The stretchable sensor networks have various applications such as fly-by-feel flights and intelligent robots.