Design, development, dynamic analysis and control of a 2-DOF spherical parallel mechanism

This paper investigates the design, dynamics, and control of a two Degrees-of-Freedom (DOFs) spherical Parallel Mechanism (PM) that was first built at Laval university. The geometric and inertial parameters of the model are obtained via a CAD software in order to reduce the weight and also to avoid the interference between the two limbs movements. The dynamic analysis used in this paper is based on a judicious concept in detaching the whole mechanism into several subsystems and consecutive synergies between kinematic analysis, Lagrangian and Newtonian approaches. The proposed approach performance for the dynamics of this mechanism is analyzed by means of several test trajectories for the end-effector and the results are put into contrast by the ones obtained with a dynamic analyser software. The results obtained by both approaches are coherent which affirms the correctness of the proposed algorithm. Finally, a co-simulation between MATLAB and MD-Adams has been accomplished in order to control this mechanism via computed torque method. The latter method has led the end-effector to follow the desired trajectory.