Forward displacement analysis for 5TSP-PPS parallel mechanism of large aperture grating tiling

To meet requirement of heavy load, high precision and high stability of heavy caliber grating tiling device, 5TSP-PPS parallel mechanism is put forward, and screw theory is adopted to analyze mechanism theory of the mechanism to realize two-dimension movement and three-dimension movement (2T3R) of space. Take TS rod length as constraint condition and establish constraint equation on the basis of vector method and deduct nonlinear equation system of forward position and inverse position. To improve computational efficiency of forward position, apply simplified Newton method to forward position analysis. Numerical example shows that: compared with Newton, simplified Newton method can improve computational efficiency of forward position. Attitude error between computational result of forward position and given pose is lower than 8.5×10^-9 μrad and location error is lower than 8×10^-10 μm, which verifies correctness of forward position analysis of 5TPS-PPS parallel mechanism. The research lays a foundation for further study of calibration of new heavy caliber grating tiling device, error analysis and real-time control of closed position loop.