Parameter estimation and anomaly detection while cutting insulation during telerobotic satellite servicing

For satellite servicing, it is necessary to remove a patch of multi-layer insulation (MLI) that covers the access panel. We consider the case where this patch is secured by tape and desire to use ground-based teleoperation to carefully cut the tape on three sides of the patch. Communication delays of several seconds motivate the development of an online method to enable failure detection by the remote (on-orbit) robot system, so that cutting can be stopped without having to wait several seconds for the ground-based operator to observe the failure. This method is based on a model that predicts the force in the direction of cutting. The model parameters are provided by a recursive least squares estimator, with vector-like forgetting factors, that also includes a throttling mechanism to ensure that the estimator is used only when operating conditions and measurements enable reasonable outcomes. During cutting, the predicted force is compared to the measured force to detect various types of failures. Experiments are conducted on a ground-based platform to demonstrate that the proposed estimation system can reliably detect these failures.