In 1989 Martin Bühler and Daniel E. Koditschek produced a juggler with one rotating bar, moving one way then the other, that bounces two-props in a fountain of indefinite length.
[1] Sakaguchi et al. (1991) and Miyazaki (1993) produced a one-armed two-ball fountain juggler with a two degrees of freedom arm and an unactuated funnel-shaped hand.
[5] Ploeger et al. (2020) achieved stable two-ball juggling in a column pattern for 33 minutes on a four degrees of freedom robotic arm with a funnel-shaped hand using a learning based approach.
[6][7] By 2011 students at the Department of Control Engineering at Prague's Czech Technical University built a 5-ball cascade juggling robot whose arms have both vertical and horizontal motion, whose hands are ring-shaped, and which contains a basket that provides the initial throws and relaunches any failed catches.
[8][9][10] Disney Research is developing a robot capable of pass juggling with the goal of being able to provide more physical interaction between visitors and mechanized characters.