ABSTRACT
This chapter explains the advantages and disadvantages of spatial mechanisms and the ongoing aim of spatial mechanism modeling, intermediate and total spatial kinematics of the revolute-revolute-spherical-spherical (RRSS), the revolute-spherical-spherical-revolute (RSSR), and the revolute-revolute-revolute-revolute (4R) spherical mechanisms, planar mechanism kinematic analysis using spatial mechanism kinematic models. Spatial mechanisms can exhibit three-dimensional or spatial motion. Spatial mechanism motion is predominantly determined by the degrees of freedom of the mechanism joints used and spatial orientation of the joints. Because spatial mechanisms have the capacity to exhibit 3D motion, they offer a greater variety of possible motions and are structurally more general than planar mechanisms. Suh and Radcliffe presented displacement, velocity, and acceleration equations for the RRSS and RSSR mechanisms. These displacement equations can be directly applied to the 4R spherical mechanism and even the planar four-bar mechanism.
