On multirate control of a fast-rate beam steering system using slow-rate image sensor feedback

This paper demonstrates the use of a slow-rate image sensor for control of a fast-rate beam steering system. The image sensor is modeled as an integrative intensity sensor, from which fast-rate dynamics may be estimated by appropriate motion-field extraction. These fast-rate state estimates obtained from the slow-rate image sensor are then used for a multirate model-following controller that achieves desired performance through state-matching. This is in contrast to traditional control schemes for fast-rate systems with image sensors, which rely on the slow-rate time-averaged output measurement during the exposure time of the image sensor (i.e., the first spatial moment of the acquired image), discarding the image blur as noise. We demonstrate that the proposed multirate feedback controller, which uses the entire intensity distribution at the image sensor, provides superior tracking performance than a similar multirate controller that uses only the first moment of the image (time-averaged output) as feedback measurements.