Improvement of the Static and Dynamic Behavior of a Milling Robot

Because of the high flexibility and low investment costs, industrial robots are increasingly being employed for machining processes. However, milling robots can only be used for applications requiring low accuracy and minor cutting forces. The main reason for this is the low static and dynamic stiffness of the robot structure, which lead to huge deflections of the tool and heavy chatter oscillations, especially when steel is being machined. To extend the areas in which milling robots are applied, a model-based controller to compensate for path deviation has been developed at the Institute of Machine Tools and Industrial Management of TU Munich (iwb). In addition, process-based strategies to reduce chatter have been analyzed. This paper focuses on the dynamic behavior of robots to increase the stability of the cutting process, but it also gives an overview of the design of the controller for static deviation compensation.