Configuration design and dimensional synthesis of an asymmetry 2R1T parallel mechanism

摘要

This paper focuses on configuration design, dimensional synthesis, and engineering application of a novel asymmetric2R1T parallel mechanism (PM) with zero-coupling degree. The analytical forward and inverse displacementsolutions are deduced by the means of vector method. The mathematical models between Euler angles and the orientationalparameters (i.e., azimuth and tilt angles) of the offset output axis are established. Using screw theoryas mathematical tool, this paper worked out evaluation indices of motion/force transmissibility and presented thedefinitions and calculation methods of good transmission orientation workspace and good transmission orientationcapacity (GTOC). Furthermore, a comparative example with respect to kinematic performance of asymmetricUPS-RPU-PU PM and planar symmetric 2UPS-PU PM is carried out, and the result demonstrates that UPS-RPUPUsignificantly outperforms 2UPS-PU in terms of GTOC. The constrained optimization model is constructed toformulate optimal problem of dimensional parameters on the maximizing GTOC, which is then solved by differentialevolution algorithm. Finally, an engineering case demonstrates that the optimized mechanism has a goodapplication prospect in hydraulic support test bed.