Task-level robot learning: juggling a tennis ball more accurately

Results are presented from a preliminary investigation of task-level learning, an approach to learning from practice. The authors programmed a robot to juggle a single ball in three dimensions by batting it upwards with a large paddle. The robot uses a real-time binary vision system to track the ball and measure its performance. Task-level learning consists of building a model of performance errors at the task level during practice, and using that model to refine task-level commands. A polynomial surface was fitted to the errors in the path which the ball took after each hit, and this task model is used to refine how the ball is hit. This application of task-level learning dramatically increased the number of consecutive hits the robot could execute before the ball was hit out of range of the paddle.