Hierarchical Learning for Robotic Assembly Tasks Leveraging LfD
Siddharth Singh, Qing Chang and Tian Yu
Abstract
Robotic assembly in manufacturing settings are a special type of long horizon Task and Motion Plan ning (TAMP) problem. While divising a motion plan for the robot is itself a challenging, identifying a task and learning it adds to problem’s complexity. This paper proposes a Hierarchical Learning (HL) based approach which pivots the multi-level structure to seamlessly integrate task identifica tion and sequencing with robot motion planning. Given the final assembly goal the higher-level agent emphasizes comprehending tasks and learning task plans. It generates sequences of sub-tasks, while the lower-level agent concentrates on executing the current sub-task. The higher-level agent employs a goal driven reinforcement learning (RL) approach to master the sequencing task, allowing it to adapt to unseen assemblies. Meanwhile, the lower level adopts a Learning from Demonstration (LfD) approach for motion planning, which can learn primitive skills from one-time demonstration and intel ligently combine the primitive skill for complicated tasks. The critical contribution of this work lies in the development of a novel method capable of comprehending and executing long horizon goal-driven assembly tasks without relying on expert demonstrations or explicit description of the whole assem bly. The proposed approach is validated through simulation and physical setup.
Video Abstract
Methodology
Training
Pick & Place
Stacking
Stacking around Wall
Comparison against Greedy Reward Shaping
Execution
Execution in Simulation
Execution Task in Simulation Setup
Execution in Simulation
Execution Task on Physical Setup
Example of execution using Kinova Gen3 (7DoF) arm.