Design and analysis of full-configuration decoupled actuating reconfigurable parallel spherical joint

Different from the existing methods by using singularity of parallel mechanism (PM) to synthesize reconfigurable PMs, a kind of actuating reconfigurable parallel spherical joint (Sm) which can realize one-dimensional fixed axis rotation and one-dimensional variable axis rotation, two-dimensional and three-dimensional rotation is synthesized. According to the characteristics of the rotation matrix, the triangle decoupling condition with lower triangular Jacobian matrix of Sm is derived. The kinematics of the Sm is analyzed, and the decoupling property of the mechanism in each configuration is verified. Based on the decoupled Sm (Sdm), the multi-mode PM 2-SdmPU/SPS which can realize the motion of invariable axis rotation and one-dimensional variable axis characteristics is proposed. This reconfigurable method can effectively avoid the singularity in the process of PM reconfiguration, and this method of realizing Sm by a convenient opening and locking actuation joint with self-locking motor is also applicable to the design of other reconfigurable mechanisms.