Simultaneous rotary and linear displacement sensor based on soft pneumatic sensing chambers

Specific industrial or research applications necessitate specialized displacement measurement conditions, thereby driving researchers to innovate sensors based on novel operating principles. One such challenging condition is the prevalence of strong electromagnetic waves, which precludes using any sensor with a metallic structure or one that operates on electrical measurement principles. Additionally, space constraints in applications requiring multidimensional displacement measurements mandate the development of sensors capable of measuring displacements simultaneously in multiple directions. This paper introduces a novel soft sensor designed to simultaneously measure linear and rotational displacements using Soft Pneumatic Sensing Chambers (SPSCs). This sensor is unique in its ability to measure both linear and rotational movements and, due to its Electro-Magnetic Compatibility (EMC) and compact size, is suitable for environments with significant electromagnetic interference and spatial constraints. Furthermore, its flexibility makes it appropriate for body-interacting applications. The Abaqus software was employed to optimize the operating parameters. Subsequently, a laboratory setup was assembled, and the sensor's performance was assessed using two calibration methods: mathematical modeling and machine learning. According to the machine learning method, the accuracy in the linear and rotational directions was 0.49 mm and 5.4°, while the Root Mean Square Error (RMSE) was 0.05mm and 0.48°, respectively.