Kinematic analysis of a new five-bar spherical decoupled mechanism with two-degrees of freedom remote center of motion

A new Spherical Decoupled Mechanism is presented in this paper. It can be consider as a new 5-bar spherical linkage or as a parallel mechanism. Indeed, a platform connected to a base by the mean of two serial spherical arms. Its new specific characteristics allow generating a Remote Center of Motion of two angular decoupled Degrees of Freedom. The decoupled motion is proven by its kinematic and velocity models. Both models are simpler than most of the decoupled mechanisms reported in the literature. Their analysis demonstrate a very simple control. It also provides the suppression of the parallel singularity inside its workspace that the original five-bar spherical linkage suffers from and its operational workspace is consequently larger. Its kinematic performance is also improved for the same linkage sizes. Moreover, this new mechanism concept appears to be very simple both in terms of kinematics compared to the original five-bar spherical linkage and in terms of design, compared to other decoupled mechanisms. A mechanism prototype is manufactured to validate the kinematic concept.