Today, industrial robots are mainly designed for and used in large-size enterprises. Typical applications are highly repetitive procedures, e.g., in the automobile production, saving costs, augmenting productivity and eliminating dangerous works. The production scenario of small and medium size enterprises (SMEs), however, differs from these tasks. Due to smaller lot sizes, SMEs require more flexible robots that can be adapted easily to constantly changing products. On the other hand, typical SMEs applications include metal working, for which a stiffer and more accurate robot is needed. The parallel kinematic Gantry-Tau manipulator has the potential to fulfill the requirements of a robot for an SME. With its parallel structure it is stiffer than commonly used serial robots, without having the disadvantage of a small workspace-to-footprint ratio typical for parallel robots. It can be constructed in a modular way thus making reconfigurations for new products possible.

To the purpose of high-bandwidth force control to be used in manufacturing operations, mechanical compliance as well as force-controlled dynamics require attention. Compliance modeling is an important part of the performance evaluation for applications using force control. For a good performance of applications like grinding, a stiff robot is desired without resonances at frequencies that could be excited during those tasks. The compliance of the Gantry-Tau robot was studied by simulations within the SMErobot project. Until this work was done, however, it was not evaluated by experimental measurements. This  work presents results of compliance dynamics identification of a Gantry-Tau robot prototype for evaluating the prototype’s suitability for applications where a stiff environment contact is desired. A vision system for measuring the end-effector position was developed. The results of the vision measurements were confirmed by laser tracker measurements.