Observer Based Fixed-Time Tracking Control for Hypersonic Gliding Vehicle

The paper studies the path tracking problem under unknown disturbance for hypersonic gliding vehicle (HGV). Based on dynamic framework of HGV, a fixed-time path tracking control method with disturbance observer is proposed by using the fixed-time control method. Firstly, a disturbance observer for HGV is addressed to let the estimation of unknown disturbances decrease to zero in finite time. Secondly, a fixed-time control law which mainly control the position is addressed to get the virtual control commands. To design actual control inputs, we proposed a two-level fixed-time feedback control method, where a fixed-time state filter is designed. It can avoid "explosion of complexity" problem. The proposed scheme allows vehicle to fly on the required path within a finite time, and this time can be bounded by designing controller parameters. Finally, consider the actual mission, we design the numerical simulations, the experimental result verifies the performance of the control strategy.