Stable cargo transportation of partial space elevator with multiple actuators

Abstract

This work proposes a novel hybrid control scheme to stabilize a partial space elevator with unknown tether tensions in cargo transportation. The tether tensions are first estimated by a new observing method. The control scheme contains two controllers. With the estimated tensions, Controller I predicts the optimal reference climber speed implemented by the actuator on the climber. When the climber is moving at the reference speed, a novel observer-based super twisting sliding mode control law is proposed for Controller II to eliminates possible disturbances and further stabilises the system in real-time. Simulation results reveal that with the observed tensions, the proposed hybrid control scheme is very effective and accurate in stabilizing the partial space elevator actuated by multiple actuators in the cargo transfer period.