This paper deals with the design of a two-degree-of-freedom spherical electrical actuator for mobile robotic applications. It presents the different steps involved in this design, namely the choice of the actuation principle, the modelling of the motor (including the electromechanical) the sizing and the manufacture of a first prototype.
Dehez, B., Grenier, D., & Raucent, B. (2002). Two-degree-of-freedom spherical actuator for Omnimobile ROBOT. Proceedings 2002 IEEE International Conference on Robotics andAutomation (Cat. No.02CH37292), Vol. 3, p. 2381-6. https://doi.org/10.1109/ROBOT.2002.1013588