Mechanical Behaviour, Contact Pose Estimation, and Finite Element Analysis of Vision Based Tactile Sensors Fabricated by Molding and Direct Ink Writing: A Comparative Study

This work pioneers the application of direct ink writing (DIW) to fabricate elastomeric additively manufactured vision based tactile sensor (VBTS). DIW cuts down the fabrication time by 76%, allowing design precise control and reducing the complexities of the process compared to the state-of-the-art (SOTA) molding techniques. Successful fabrication of DIW sensor is verified in three stages. Firstly, the mechanical characteristics of the DIW sensor are at par with those of SOTA molded Ecoflex in terms of depth of compression, compression rate, and the number of cycles. Secondly, using robotic pose estimation as a demonstration, the force enables deformation in the DIW sensor shows comparable normality estimation performance to that of the SOTA Ecoflex with a mean absolute error of less than 0.6°. Thirdly, finite element analysis (FEA) of DIW and SOTA Ecoflex sensors using Yeoh model shows similar stress and strain distributions as another evidence of DIW deformability and durability signaling sensor's successful fabrication.