US Patent 10189342 Ball-balancing robot and drive assembly therefor

A ball-balancing drive assembly includes a ball having a ball surface and a reference axis extending through a centroid of the ball. Three omniwheel assemblies, each having a motor with a motor axle and an omniwheel configured to rotate around the motor axle are mounted on a chassis configured for supporting the three omniwheel assemblies at radially symmetric spacings with the motor axles oriented at an angle relative to the reference axis and the omniwheels oriented in mutually-orthogonal planes. Each omniwheel frictionally contacts the ball surface to convert rotational motion of the motor axle to torque on the ball.