Potential of manipulating the damping properties of parallel kinematic machine tools

Pentapod and hexapod structures consist of 5 or 6 kinematic chains linked to one another. These chains are generally formed of one strut, the corresponding number of joints and an advance drive. It is necessary to set up the joints in a very tight space and design struts as slim as possible to generate the best kinematic properties and high axis dynamics. The joints are best formed of pretensible combinations of roller bearings that only dampen slightly. These design constraints mean that the joints are much less rigid than the guide systems for serial machine structures, although they only have slight flexural strength. This results in higher vibration susceptibility with simultaneously limited system damping. At the same time, its vibration properties are substantially more complex and therefore more difficult to capture due to the interlinked kinematic chains, the large number of discrete elasticity points and greater position dependency.