Design of a high speed parallel mechanism based on Virtual Force Redundancy concept

This paper discusses design of a high speed parallel mechanism for electronic part mounters. First, a typical four degree of freedom pick-and-place motion is analyzed, and the basic concept of the virtual force redundancy (VFR) during the motion is proposed to design high speed parallel mechanisms. Second, a basic structure of the high speed parallel mechanism using the newly designed constrained differential drive mechanism (CDDM) is proposed based on this concept, and the kinematical design of its prototype is described. Then, the expected driving force and acceleration at the endpoint of the proposed structure are analyzed comparing with the properties of a typical XY table. Finally, some experiments are executed using the prototype of the proposed structure to identify the dynamic parameters of the CDDM, and the acceleration property and the frequency property of the CDDM are experimentally obtained to investigate the validity of the VFR concept.