Analysis of force producers in hemispherical stepper motor

An arm can spin in a conical space through a ball-socket system. The extension of the arm increases the height of the cone and the area of its base. In this the mover cannot perpendicularly approach the surface of a 3-D object, if the socket is not moved by further additional motors and corresponding arms. In such a system an end-effector cannot effectively operate over a curved surface/3-D object. This paper discusses design, analysis and fabrication of a hemispherical system (based on solenoids as force producers) whose mover can actuate a wrist joint motion while moving over a pre-defined 3-D (stationary) object under a digital position controller. The force producer unit of this system is based on a solenoid which necessitates a deep analysis of its propulsion force leading to improvement of force-to-weight ratio of the mover. The FEM analysis of propulsion force has been done using software ANSYS 5.0.