In this paper, first the application of Homotopy Continuation Method (HCM) in numerically solving kinematics problem of spatial parallel manipulators is investigated. Using the HCM the forward kinematics problem (F-Kin) of a six degrees of freedom (DOFs) 6–3 Stewart platform as well as the inverse kinematics problem (I-Kin) of a 3-DOF 3–PSP robot are solved. The governing equations of the kinematics problems of the robots are developed and embedded in the homotopy continuation function. The HCM is utilized in order to solve the nonlinear system of equations derived from the kinematics analysis of the robots. Then, to represent the real case application an initial guess far from the correct answer is selected. It is shown that, comparing with the Newton-Raphson method (NRM), the F-Kin calculation time for the Stewart robot is decreased by 43%. Therefore, using the HCM a hybrid method is suggested to solve the F-Kin of the Stewart robot. Furthermore, the HCM, as an innovative method, relieves other downsides of the conventional numerical methods, including a proper initial guess requirement as well as the problems of convergence.

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