Weighted kinematic sensitivity of a 4-DOF robot

摘要

In this paper, kinematic modeling and weighted kinematic sensitivity of a 4-DOF parallel robot called Tesserataar, performing 3 translational and one rotational motion pattern are investigated. The conventional kinematic sensitivity index has the drawback of ignoring different sensitivity to the active joints uncertainty. Thus, weighted kinematic sensitivity is proposed to cover this drawback. In the proposed approach, different sensitivity of actuators by implementation of Sobol's sensitivity analysis method is obtained. To do so, first, weighted kinematic sensitivity is introduced and its formulation is illustrated. For calculating the weight matrix, Sobol's sensitivity analysis method is used. In order to present the application of the proposed method, Tesserataar robot is considered as a case study. Thus, in this paper, a new index refer to as weighted kinematic sensitivity of the Tesserataar is obtained. A cube meshes of robot workspace is taken into account in order to avoid singularities within the workspace. Weighted kinematic sensitivity is calculated over the meshes in robot workspace. Conventional and weighted kinematic sensitivity of Tesserataar robot are compared. From the obtained results it can be inferred that standard method predicts sensitivity more conservative and the proposed method is more realistic and close to the reality.