Design and parameters optimisation of fused deposition modelling (FDM) technology in the fabrication of sensorised soft pneumatic actuator

The design and printing parameter optimization for soft pneumatic actuators (SPAs) performance remains underexplored, particularly for sensorised SPAs. Therefore, in this study, the influence of design (sensor shape and SPA's chamber shape) and printing parameters (Nozzle temperature, Layer thickness, Infill angle, and Speed) in the fabrication process of sensorised SPA is investigated to achieve an optimal performance, focusing on bending characteristics (deformation angle, length, diameter) and sensor resistance. A sensorised SPA was successfully fabricated using dual-material and dual-extruder fused deposition modeling (FDM) technology, employing flexible TPU filament for the SPA structure and thin-layer printed ABS conductive filament as the strain sensor. The results demonstrated that the optimal SPA and sensor shapes varied depending on the specific performance metrics. Using the Grey Relational Analysis (GRA) method integrated with Taguchi analysis, the study identified parameter combinations that yielded optimal results for each metric. The SPA shape proved to be the most influential factor in determining SPA bending performance, specifically contributing 88 to the angle, 89 to the diameter, and 57 to the length. In contrast, sensor shape and layer thickness had an equally substantial impact on sensor resistance, each accounting for 32 of the observed variation. This study successfully integrated TPU and thin-layer printed conductive ABS for the sensorised SPA, resulting in a low-cost fabrication process. However, the resistance values obtained were relatively high, indicating the need for further development in future research. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.