Physics-Aware Robotic Palletization with Online Masking Inference

-- The efficient planning of stacking boxes, especially in the online setting where the sequence of item arrivals is unpredictable, remains a critical challenge in modern warehouse and logistics management. Existing solutions often address box size variations, but overlook their intrinsic and physical properties, such as density and rigidity, which are crucial for real-world applications. We use reinforcement learning (RL) to solve this problem by employing action space masking to direct the RL policy toward valid actions. Unlike previous methods that rely on heuristic stability assessments which are difficult to assess in physical scenarios, our framework utilizes online learning to dynamically train the action space mask, eliminating the need for manual heuristic design. Extensive experiments demonstrate that our proposed method outperforms existing state-of-the-arts. Furthermore, we deploy our learned task planner in a real-world robotic palletizer, validating its practical applicability in operational settings. I. INTRODUCTION In modern warehouse and logistics management, stacking boxes continues to be a common challenge. In the past, due to the smaller scale of trade and lower efficiency requirements, workers could rely on their experience to decide how each box should be placed. However, with the globalization of trade, there is a growing need for fast and stable box stacking, and a good solution for this is robotic palletization [1] [2].