Global kinetostatic modelling of tripod-based parallel kinematic machine

In this paper, a new method is presented for global kinetostatic analysis of parallel kinematic machines (PKMs). First, a complete compliant model is developed for Tripod-based PKMs. It includes three types of flexibility, namely, actuator flexibility, leg bending and leg axial flexiblity. Second, based on this model, two global compliance indices are introduced to provide a means of measuring the PKM’s compliance over the workspace. Third, the effect of three types of compliance is investigated in order to identify a dominant factor. The proposed method is implemented to analyze the compliance of the Tripod-based PKM prototype built at the Integrated Manufacturing Technologies Institute of the National Research Council of Canada. Finally, a comparison study is carried out on various tripod units proposed in the literature including Tricpet, Z3 Head, Georg V and Tripod.