Design and implementation of a spherical joint for mobile manipulators

The design of a service robot from scratch, that is able to act in usual human environments, is a challenging task. In this paper, the design of a 3-DOF joint is presented that can be used as torso, neck or wrist joint for a mobile manipulating service robot. As torso joint, it extends the workspace of manipulators while keeping the robot stable, as neck joint it can increase the field of view in case of head-mounted sensors. Thanks to its round design, it facilitates safe design, despite it moves powerfully a big part of the robot. The coupled mechanism reduces joint torques and thereby power consumption, costs and space needed for the construction. The 3-DOF rotation around a virtual point also enables gestures and agile movements.