Dynamic analysis and design of a 6-dof parallel mechanism based on 6-PUS kinematic chains

In this thesis the analysis of a 6-dof robotic platform based on the parallel architecture of Hexaglide has been performed. The objective of the mechanism under study is to be applied as a test rig to perform unsteady aerodynamic experiments inside the wind tunnel. The 6-dof platform is intended to function as emulator in the loop of the sea to simulate the real working condition of the offshore structures. Hexaglide, is a 6-dof fully parallel manipulator with 6 independent kinematic chain of PRRS type. Each kinematic chain is consist of an actuated prismatic joint on the base which is followed by a universal joint connecting the constant length link to the sliding body, which itself is followed by a spherical joint on the connection between link and platform. Despite the advantageous performance features of parallel robots in terms of precise accuracy, fast operation speed, and high load capacities with respect to classic serial manipulators their application have been limited in practice. This is mainly due to their complexity of kinematics and dynamics problem which lead to difficulty of establishing a control law based on the dynamic model. The analytical method to solve the inverse kinematic problem of the Hexaglide architecture has been represented. Also a formalism based on Newton-Euler equations of motion for the dynamic model is included. Then the multibody dynamics software Adams has been applied to perform the simulations. Based on the results of the dynamic simulation the design features of the robot have been discussed.