Finite-time prescribed performance control for approaching non-cooperative target’s feature surface

In this paper, a model-free finite-time control method based on the prescribed performance control theory to solve the position and attitude coupled control problem of using small satellite to approach large non-cooperative target’s feature surface is proposed. Firstly, an accurate dynamics model is established to analyze the strong uncertainty of this nonlinear system. Then, relying on using an improved extended state observer to identify complex controlled system, the proposed method utilizes a finite-time performance function to perform homeomorphic mapping of position and attitude tracking errors and designs a feedback linearization control law to reconstruct the system into a decoupled multidimensional second-order linear system. While proving the finite-time stability of the designed performance function, parameter rules considering the discrete output of the actuator are also provided. Compared to others, the algorithm in this study is simpler and more scalable. Finally, the numerical simulation results show that the designed control algorithm meets the position and attitude accuracy requirements of in-orbit service and can achieve high-quality finite-time control without relying on precise prior models.