High performance visual servoing for controlled µm-positioning

The research presented in this paper focuses on high performance visual servoing for controlled positioning on micrometer scale. Visual servoing means that the positioning of a x-y table is performed with a camera instead of encoders and one camera image and image processing should determine the position in the next iteration. With a frame rate of 1000 [fps], a maximum processing time of 1 millisecond is allowed for each image (132 × 45 pixels). The visual servoing task is performed on an OLED substrate, which can be found in displays, with a typical size of 80 by 220 μm. The repetitive pattern of the OLED substrate itself is used as an encoder and thus closing the control loop. We present the design choices made for the image processing algorithms and the experimental setup as well as their limitations.