Variable Actuation Modes in Parallel Manipulators: Impact on the Stiffness Behavior

The paper deals with the analysis of the manipulator actuation mode on the manipulator stiffness behavior. The main scientific contribution of the paper related to advancement of Matrix Structural Analysis (MSA) technique for the case of complex open-loop and closed-loop manipulators. The proposed approach presents the manipulator stiffness model as a homogeneous set of matrix equations describing the link properties that are complemented by a set of constraints describing connections between links that are presented in a similar way as link models. The proposed approach straightforwardly aggregates the stiffness model equations avoiding merging of columns and rows usually used in conventional MSA approach. The efficiency of this approach is illustrated by comparison analysis of NaVaRo manipulator for different actuation modes.