Tethered system deployment controls by feedback fuzzy logic

Feedback controls based on a simple fuzzy-logic rule and minimal measurements for in-plane tether deployment control problems with tethered end-mass deployment terminal position and phasing time constraints or objectives, such as tether initiated waste-disposal and capsule re-entry applications, are proposed and illustrated in the present paper. The fuzzy logic law of the proposed rate feedback control solution to the in-plane deployed tether terminal position-only problem has been associated with the tether length-angle state plane, instead of its full state space or the physical deployment trajectory plane. Simulation results showing high robustness characteristics of the numerically implemented terminal angle-length control solution to main system parameter changes and uncertainty for a nominal tethered system model, with specified deployer configuration design and operational strategy, are also presented. Solutions to the more complex space-time tether deployment control problem, with terminal deployment angle-length-time constraints and associated with a tether initiated capsule re-entry application, have also been formulated and presented as extensions of the previously stated deployment terminal position control, together with numerical simulation results for the nominal tethered system model and deployer configuration. (C) 1997 Elsevier Science Ltd.