Modelling of Uniaxial EGaInBased Strain Sensors for Proprioceptive Sensing of Soft Robots Soft strain resistive sensors based on eutectic galliumindium liquid metal can play an important role in proprioceptive sensing for soft robots. However, there are no available mathematical models to accurately estimate the strain as a function of the measured resistance. Furthermore, nonuniform strain in the microchannels has not been analysed yet. In this paper, we introduce a new model to estimate the strain or elongation in submillimetre scale, and analyse its accuracy through a customised testing setup and procedure. The effect of strain rate on the measurement accuracy is also studied. We compare existing theoretical models with our experimental results, and discuss the differences between them. Moreover, we analyse the effect of strain rate on hysteresis caused by the viscoelastic behaviour and introduce a new model for it to be potentially used for future work. This paper demonstrates, among other things, that rational models could provide high accuracy in strain estimation, and might help to enhance proprioceptive sensing and state control of soft robots.

Modeling, Simulation and Experimental Validation of a Tendondriven Softarm Robot Configuration  A Continuum Mechanics Method This paper presents the mathematical derivation and experimental validation of a computational model, which accurately predicts static, largestrain deformations of tendon driven nonslender softarm manipulators subjected to gravity. The large strain behaviors are captured by employing the GreenLagrange strain and by deriving analytical expressions for the variation of the equivalent Young modulus of the structure due to the large strains. No simplifying assumptions are made regarding the curvature of the structure, the stretching or the compression. Furthermore the paper proposes an iterative method for numerically solving the resultant nonlinear system of coupled differential equations and demonstrates a number of application scenarios. The model is experimentally validated using a setup comprising one segment of tendon driven softarm, which integrates stretchable and compressible hyperelastic (rubbertype) materials into its nonhomogeneous back bone structure.