Physics-Guided Hierarchical Reward Mechanism for Learning-Based Object Grasping

Learning-based grasping can afford real-time motion planning of multi-fingered robotics hands thanks to its high computational efficiency. However, it needs to explore large search spaces during its learning process. The search space causes low learning efficiency, which has been the main barrier to its practical adoption. In addition, the generalizability of the trained policy is limited unless they are identical or similar to the trained objects. In this work, we develop a novel Physics-Guided Deep Reinforcement Learning with a Hierarchical Reward Mechanism to improve the learning efficiency and generalizability for learning-based autonomous grasping. Unlike conventional observation-based grasp learning, physics-informed metrics are utilized to convey correlations between features associated with hand structures and objects to improve learning efficiency and outcomes. Further, a hierarchical reward mechanism is developed to enable the robot to learn the grasping task in a prioritized way. It is validated in grasping tasks with a MICO robot arm in both simulation and physical experiments. The results show that our method outperformed the standard Deep Reinforcement learning method in task performance by 48% and learning efficiency by 40%.