Tether operations using fuzzy logic based length control

The authors developed a fuzzy logic based tether length controller into the tethered satellite system 1 (TSS-1) simulation to investigate the usefulness and robustness that can be achieved with fuzzy control. They report the performance of the controller with the bead dynamics model, also known as the finite element model. The tether mass is represented as a lumped mass in a head, and the entire tether length is divided into several segments, thus making several beads with three degrees of freedom motion in the orbital environment. The algorithm based on fuzzy logic for controlling tether length is described, and details are provided of the membership functions and rule base. The results comparing the performance in terms of length error, tension error, and librational oscillations are presented