Predictive Body Awareness in Soft Robots: A Bayesian Variational Autoencoder Fusing Multimodal Sensory Data

Predicting the causal flow by fusing multimodal perception is fundamental for constructing the bodily awareness of soft robots. However, forming such a predictive model while fusing the multimodal sensory data of soft robots remains challenging and less explored. In this study, we leverage the free energy principle within a Bayesian probabilistic deep learning framework to merge visual, pressure, and flex sensing signals. Our proposed multimodal association mechanism enhances the fusion process, establishing a robust computational methodology. We train the model using a newly collected dataset that captures the grasping dynamics of a soft gripper equipped with multimodal perception capabilities. By incorporating the current state and image differences, the forward model can predict the soft gripper's physical interaction and movement in the image flow, which amounts to imagining future motion events. Moreover, we showcase effective predictions across modalities as well as for grasping outcomes. Notably, our enhanced variational autoencoder approach can pave the way for unprecedented possibilities of bodily awareness in soft robotics.