Robot-Driven Autofocus Control Mechanism for an In-hand Fixed Focus Camera

The manufacturing industry is looking into more flexible solution for SMEs, in order to cope with few-of-a-kind production. Short set-up time and no need for experts is a requirement, which is why learning of assembly is done by kinesthetic demonstration. Teaching robot in-hand machine vision tasks requires positioning the robot-camera in the appropriate pose for image acquisition. The same camera is normally used for several inspections, consequently a focus distance is set on the lens. The operator must move the robot and the only feedback is the image from the camera. In this paper we proposed an autofocus control mechanism for a robot with a fixed focus camera. We evaluated the accuracy of the focus and time savings by using this method compared to manual positioning by an operator.