VaRSM: Versatile Autonomous Racquet Sports Machine

In this paper, we present a system called Versatile Autonomous Racquet Sports Machine (VaRSM in short). VaRSM can play table tennis, tennis and badminton with respective racquets. There are two major challenges in building VaRSM: first, VaRSM must be able to strike and return balls of variable speed and power on fields of different size with diverse racquet motions; second, VaRSM must track and predict balls' fast trajectories and move its body in extremely short intervals of time. To address these challenges, we design several innovative technologies, which we group into the physical hardware module and the control software module. In the physical hardware module, we create a high speed swerve-drive platform and a high-flexibility racquet arm, using configurable integrated drive units. In the control software module, we develop a proactive progressive control method that takes advantage of the hardware's physical capabilities to achieve early ball trajectory prediction, quick striking decision-making, and fast yet stable machine motion. We build a prototype system based on these technologies. Our experiments demonstrate VaRSM is able to strike and return table tennis, tennis and badminton balls with high success rates and is capable of playing with human players. To our knowledge, VaRSM is the first machine able to play three different ball games, and may hold great significance in education, research, economy, and society.