This paper details the motivation, design and outcome of the Metrology Assisted Robotic Metrology (MARA) system. This project builds on the MARA project, a previous research project at the MTC, in which a real-time correction system for industrial robots was proven successfully without End-Effector loading. MARA2 aims to assess the viability of using an external measurement system to correct an industrial robot under load during machining and trimming operations.
Using the MARA system, a robot can be made accurate over a very large volume. Robot accuracy is important when using Offline Programming (OLP) to generate paths for robots. This system could be used as a more cost efficient replacement for large purpose machine tools or to replace manual work that was previously out of reach of robot accuracy specifications.
The MARA2 project conducted a review into the current large volume metrology market and down selected the most suitable device for the system. An existing cell was then converted into a robotic machining cell with integrated spindle. A new, simplified programming workflow was created, using a traditional CAM system, robot simulation and bespoke calibration software. The system was then used to machine various feature geometries into aluminium, which were then measured and compared to non-compensated cuts. Trial results show feature accuracies of within 0.2mm are achievable in aluminium milling operations.