Kinematic study of feasibility of geared planar parallel manipulator

The paper shows an appropriate unitary study of a novel geared planar parallel manipulator with the structure 3-R (PRRGR)RR which uses geared linkages with linear actuators and slider cranks as legs. The use of geared linkages with linear actuation although with more complex structure, allows a large rotation angle with proper transmission angle in the linkages and the approximately linear transmission function within large range. A positional kinematic analysis of the 3-R (PRRGR)RR was developed with a unitary analytical model, which is worked out through a numerical example that computes the singularities of type I and II together with the local and global performance indices, namely manipulability, conditioning number, kinematic, stiffness and transmission indices. The presented results are discussed and compared with an equivalent 3-RRR planar parallel manipulator with the same links lengths to highlight the kinematic advantages of the proposed planar parallel manipulator 3-R (PRRGR)RR. The novel geared planar parallel manipulator is designed and simulated in Creo Parametric in order to validate the analytical model with a numerical performance characterization.