Parallel kinematics are on their way to the market. Different parallel and hybrid systems were proposed and realized in recent years. Due to the different structures and drive principles design possibilities are numerous. In order to be able to compare the different systems, both among each other and with conventional systems, there is a need to establish comparison criteria.
In this paper different characteristics such as workspace, stiffness and isotropy are used to evaluate the most used strut arrangements and drive types. Based on the three different drive principles, several systems and their properties are introduced. Thereby different boundary conditions (joint angles, strut arrangement) are taken into account and their influence on the system characteristics is examined. Resulting workspace and stiffness were chosen as comparison criteria. On the one hand, the ratio between the workspace and the size of the machine is considered as the main disadvantage of parallel kinematics, on the other hand, the high stiffness is the main advantage of these systems.