Smart Roller: Soft Sensor Array for Automated Fiber Placement

Rollers and wheels are widely used in industry and transportation, but there is seldom direct information about contact forces. A smart roller is introduced which provides real‐time pressure measurements from a soft, elastomer‐coated cylinder. The roller is designed for automated fiber placement (AFP) machines, which are widely used in the aerospace industry to manufacture complex composite parts. For optimum process performance, real‐time feedback is highly desirable for detecting flaws during manufacturing. The sensor replaces the elastomer outer layer of a standard roller with 4 by 13 tactile pixels (taxels) of soft capacitive sensors, which provide more than 1 pF of change in capacitance per taxel over a pressure range of 1 MPa. Sensors are made of silicone and mounted on a flexible printed circuit board on which a microcontroller with Bluetooth‐Low‐Energy collects and transmits capacitance data. The sensor dielectric layer is composed of pillars that increase layer compliance and sensitivity while also providing the stiffness of typical industrial rollers. The ability of the roller to measure real‐time local compaction pressure at typical manufacturing speeds enables the monitoring of spatially‐resolved pressure‐time curves, which can be used to predict and control adhesion.