Adhesion Sensing in an Electroadhesive Paper Handler and Its Application to Physical RPA

Recently, robotic process automation (RPA) has been widely used to automate various office tasks, but most RPA systems automate only the tasks performed on computers. To extend RPA systems to automation of physical tasks, we have been developing an electroadhesive paper handler that adheres to a sheet of paper with electrostatic attraction force caused by an application of a high voltage. Although our handler enables robots to easily handle paper, it sometimes fails to adhere to paper if the voltage application time is short. To address this issue, in this study, we propose a sensing mechanism that can detect whether the handler is adhering to the target. The sensing mechanism requires only a simple circuit and a single voltage measurement. Through experiments, we show that the sensing is possible at various humidity and temperatures and in various paper conditions. Also, we study the measured voltage's dependence on a resistance of the measurement circuit and the voltage's transient responses, and provide an equivalent circuit that explains them. Moreover, using an example robot system that automatically extracts specified documents from a given pile of documents, we show that the proposed sensing mechanism speeds up paper handling by making adhesion failures recoverable.