Web Tension Observer Based Control for Single-Span Roll to Roll Systems

Roll-to-roll (R2R) systems prove great potential for high-throughput and cost-effective production of flexible electronics, including solar cells, wearable sensors, and so on. Actually, most of design methods for tension controller of web transport system (such as paper, plastic film, etc.) require state variables as feedback. These variables can be measured directly using the sensors. However, the complex systems that have many states will require many sensors which makes the control system bulky and expensive. Moreover, direct measurements are difficult or tend to be inaccurate in many systems. In R2R systems, precise regulation of span tension is critical to ensure product quality. Elevated tension causes web fracture during operation; depressed or highly variable tension leads to irregular and unacceptable spool. The approach in this paper is to model the state observer with only a small number of sensors. Then, we will propose a method to build tension controller based on backstepping controller using the tension observer. Simulation has shown that the proposed controllers with tension observer well-perform against the inertia disturbances.