High-precision Visual Servoing in Asteroid Flyby with Multirate Feedforward Control and Trajectory Estimation

In the flyby search for an asteroid, it is necessary to precisely direct the observation mirror to the viewing angle, which changes significantly at the closest approach point. In order to develop a control law for the mirror, we have to deal with the quantization due to resolution of the camera and dead time due to image processing. This paper proposes an application of multirate feedforward control based on the estimation of relative trajectory. The proposed method reduces the tracking error generated by the influence of quantization noise and enables to keep the angular error within one pixel or less by using an estimation of the relative trajectory.