A Deep-Learning-Based Approach for Stiffness Estimation of Deformable Objects

Abstract: Object deformation is an essential factor for the robot to manipulate the object, as the deformation impacts the grasping of the deformable object either positively or negatively. One of the most challenging problems with deformable objects is estimating the stiffness parameters such as Young’s modulus and Poisson’s ratio. This thesis presents a learning-based approach to predicting the stiffness parameters of a 3D (volumetric) deformable object based on vision and haptic feedback. A deep learning network is designed to predict Young’s modulus of homogeneous isotropic deformable objects from the forces of squeezing the object and the depth images of the deformed part of the object. The results show that the developed method can estimate Young’s modulus of the selected synthetic objects in the validation samples dataset with 3.017% error upper bound on the 95% confidence interval. The conclusion is that this method contributes to predicting Young’s modulus of the homogeneous isotropic objects in the simulation environments. In future work, the diversity of the object shape samples can be expanded for broader application in predicting Young’s modulus. Besides, the method can also be extended to real-world objects after validating real-world experiments.