A Light-weight and Rapid Table Tennis Ball Trajectory Prediction Approaches towards Online Bouncing Task

It is essentially required to predict the ball's flight trajectory accurately and timely for a robotic table tennis ball bouncing task. Existing solutions, which can be categorized into model-based and learning-based groups, both exhibits unpleasant disadvantages. For example, they often require to identify many dynamic parameters accurately or to collect extensive labeled data, which are generally very difficult or costly to achieve in real world. In this paper, we proposed a light-wight and rapid trajectory prediction approach for online table tennis bouncing tasks based on a simplified model. In the proposed approach, the ball's flight poses are captured and estimated by a low-cost RGB-D camera. Then the ball's landing position is predicted in advance by using a fitted 3D parabola. Compared with existing solutions, our proposed approach is lightweight and easy to deploy. In experiments, 66 flight trajectories of the ball are collected to serve as benchmark. The prediction errors for all landing positions are all less than 20mm, in which most of them are less than 10mm. In addition, the prediction can be achieved 141.7ms in advance, which is fast enough for the robotic arm to plan and move itself to the predicted landing point.