Design of a 4-DOF hybrid PKM module for large structural component assembly

This paper presents a novel 4-DOF hybrid parallel kinematic machine (PKM), named Bicept, comprising a 2-DOF parallel mechanism plus a 2-DOF rotating head. The PKM is designed as a rigid yet compact module that can act as a robot cell moving along a long track for aircraft structural component assembly, a wing box for example. Dimensional synthesis of the 2-DOF parallel mechanism is carried out to achieve a relatively good kinematic performance within a prescribed task workspace that has a large width/height ratio. Then, using commercial CAE software, rigid body dynamics and stiffness analyses are carried out for motor sizing and performance evaluation of a full-size virtual prototype.