Fractional-order tension control law for deployment of space tether system

One of the critical issues for space tether missions is the stable deployment of the tether. Many effective control strategies and devices have been proposed for the deployment. First, it is more suitable for modeling flexible structures because of its unique historical memory effect. Second, it provides an effective and clear-cut robust control strategy, especially for distributed parameter systems. Third, it responds to control input faster, with smaller overshoots than its integer counterpart. It is shown that the stable region of classic integer-order tension control is the subset of the stable region of the fractional-order tension control. The newly proposed fractional-order control law has been discretized and implemented by the frequency approximation method and the Tustin operator. The effectiveness and advantage of the new fractional-order tension control law is demonstrated by simulation.