Benchmark of the 3-DOF Gantry-Tau Parallel Kinematic Machine

In this paper the invited session and the 4 original contributions are described first. Then the details of the first paper in the invited session is presented. In this first paper a new method for calculating the dynamic stiffness (frequency response) of parallel kinematic machines (PKMs) with six links, or Hexapods, is presented. The method assumes that each link and universal joint can be described by a mass-spring-damper model and calculates the transfer function from a Cartesian force or torque to Cartesian position or orientation. The new method has been used to benchmark two versions of the Gantry-Tau PKM, a relatively new PKM which has been designed to achieve a large workspace to installation space ratio, while at the same time achieve higher static and dynamic stiffness compared to serial-type industrial robots. The benchmark results presented in this paper show that these goals can be achieved in large sections of the workspace envelope. The benchmark also shows that machining centre specifications can be met if the location and dimensions of the work objects are known at the design stage.