DIPP: Discriminative Impact Point Predictor for Catching Diverse In-Flight Objects

In this study, we address the problem of in-flight object catching using a quadruped robot with a basket. Our objective is to accurately predict the impact point, defined as the object's landing position. This task poses two key challenges: the absence of public datasets capturing diverse objects under unsteady aerodynamics, which are essential for training reliable predictors; and the difficulty of accurate early-stage impact point prediction when trajectories appear similar across objects. To overcome these issues, we construct a real-world dataset of 8,000 trajectories from 20 objects, providing a foundation for advancing in-flight object catching under complex aerodynamics. We then propose the Discriminative Impact Point Predictor (DIPP), consisting of two modules: (i) a Discriminative Feature Embedding (DFE) that separates trajectories by dynamics to enable early-stage discrimination and generalization, and (ii) an Impact Point Predictor (IPP) that estimates the impact point from these features. Two IPP variants are implemented: an Neural Acceleration Estimator (NAE)-based method that predicts trajectories and derives the impact point, and a Direct Point Estimator (DPE)-based method that directly outputs it. Experimental results show that our dataset is more diverse and complex than existing dataset, and that our method outperforms baselines on both 15 seen and 5 unseen objects. Furthermore, we show that improved early-stage prediction enhances catching success in simulation and demonstrate the effectiveness of our approach through real-world experiments. The demonstration is available at https://sites.google.com/view/robot-catching-2025.