Active Task Randomization: Learning Robust Skills via Unsupervised Generation of Diverse and Feasible Tasks

Solving real-world manipulation tasks requires robots to be equipped with a repertoire of skills that can be applied to diverse scenarios. While learning-based methods can enable robots to acquire skills from interaction data, their success relies on collecting training data that covers the diverse range of tasks that the robot may encounter during the test time. However, creating diverse and feasible training tasks often requires extensive domain knowledge and non-trivial manual labor. We introduce Active Task Randomization (ATR), an approach that learns robust skills through the unsupervised generation of training tasks. ATR selects suitable training tasks-which consist of an environment configuration and manipulation goal-by actively balancing their diversity and feasibility. In doing so, ATR effectively creates a curriculum that gradually increases task diversity while maintaining a moderate level of feasibility, which leads to more complex tasks as the skills become more capable. ATR predicts task diversity and feasibility with a compact task representation that is learned concurrently with the skills. The selected tasks are then procedurally generated in simulation with a graph-based parameterization. We demonstrate that the learned skills can be composed by a task planner to solve unseen sequential manipulation problems based on visual inputs. Compared to baseline methods, ATR can achieve superior success rates in single-step and sequential manipulation tasks. Videos are available at sites.google.com/view/active-task-randomization/