In this paper, we present a fully soft miniaturized continuum robot that integrates 3D optical shape sensing through functionalized tubing used as soft optical waveguides. The sensor is fabricated by laser patterning an off-the-shelf medical tubing, allowing for bidirectional responses to large curvatures in two bending directions, enabling 3D shape sensing and tip tracking of the continuum robot. The robot is able to bend and sense its own shape up to a curvature of 44.7 m-1, corresponding to a bending angle of 102°, having high-accuracy tracking capabilities, resulting in an average tracking error of 3.08 mm, that is 7.7 % of the robot length. The robot’s functionality was shown in validation experiments, including a real-time shape prediction through a graphical user interface.

Soft optical sensing strategies are rapidly developing for soft robotic systems as a means to increase the controllability of soft compliant robots. In this paper, we present a roughness tuning strategy for the fabrication of soft optical sensors to achieve the dual functionality of shape sensing combined with contact recognition within a single multi-modal sensor. The molds used to fabricate the soft sensors are roughened via laser micromachining to achieve asymmetrical sensor responses when bent in opposite directions. We demonstrate the integration of these sensors into a fully soft robotic platform consisting of a multi-directional bending module with integrated 3D shape sensing and a gripper with tip position monitoring along with contact force recognition. We show the accuracy of our sensing strategy in validation experiments and a pick-and-place task is performed to demonstrate the robot's functionality.