Flexible Force Control for Accurate Low-Cost Robot Drilling

The problem of robot drilling presents a significant challenge, due to the comparatively low mechanical stiffness of typical serial industrial robots. This compliance makes the robot deflect due to the cutting forces, resulting in poor hole quality. Recently, functionality for high-bandwidth force control has found its way into industrial robot control systems. This could potentially open up the possibility of robotic drilling systems with improved performance, using only standard systems without costly extra hardware and calibration techniques. In this paper, we present methods and systems for force-controlled robot drilling, based on active suppression of drill sliding through a model-based force control scheme. The methods are validated in a number of drilling experiments using an industrial robot.