Adaptive Fixed-Time Six-DOF Tracking Control for Noncooperative Spacecraft Fly-Around Mission

Fixed‐time attitude tracking control for spacecraft based on adding power integrator technique

“…Based on NTSMC, Reference designs a fixed‐time controller for attitude stabilization. A fixed‐time attitude tracking controller is developed based on Sin‐FM in Reference . Two fixed‐time attitude controllers are given based on ASMM for attitude stabilization and attitude tracking in References , respectively.…”

“…As mentioned in the above paragraph, TSM methods have some weaknesses. Therefore, the bound of settling time in Reference may tend to infinity when states converge to zero; there exists an unknown period of time in the complete bound of settling time in Reference and the bound of settling time in References and may tend to infinity if states converge along with the asymptotic sliding mode surface. Although the fixed‐time control method in Reference has no singularity problem and it can give a complete bound of settling time, the exponent parameters are fixed and it is difficult to use this method to design a continuous attitude controller for spacecraft, even if disturbance is not taken into account.…”

“…In comparison with most of the finite‐time attitude controllers that are based on the conventional concept of finite‐time stability, such as the homogeneous attitude controllers, the terminal sliding mode attitude controllers, and the “AAPIC” attitude controllers, two novel attitude controllers are designed based on the concept of “fixed‐time stability,” which can be seen as a special case of finite‐time stability Compared with most of the existing fixed‐time attitude controllers that are designed based on the TSMC, such as those in References , the two proposed fixed‐time controllers are designed based on the AAPIC. In comparison with the research results related to finite‐time attitude control, such as those in , this study further considers the case where external disturbance and thruster faults exist. Moreover, compared with many discontinuous finite‐time controllers, the two proposed controllers are continuous. …”

Adaptive fixed‐time fault‐tolerant control for rigid spacecraft using a double power reaching law

“…In the work of Polyakov, the fixed‐time control approach is proposed, and the upper bound of the convergence time is unrelated to the initial conditions. Consequently, the fixed‐time control has gained much attention, and various research works have been presented . In the work of Gao and Cai, based on the quaternion and Lagrange‐like spacecraft dynamics, robust fixed‐time controllers were constructed to guarantee the fixed‐time convergence of the attitude tracking errors subject to inertia uncertainties and external disturbances.…”

“…Consequently, the fixed-time control has gained much attention, and various research works have been presented. [33][34][35][36][37] In the work of Gao and Cai, 35 based on the quaternion and Lagrange-like spacecraft dynamics, robust fixed-time controllers were constructed to guarantee the fixed-time convergence of the attitude tracking errors subject to inertia uncertainties and external disturbances. In the work of Jiang et al, 36 considering the actuator saturation and faults, a fixed-time sliding mode control scheme was proposed to achieve the attitude stabilization of the rigid spacecraft.…”