Adaptive attitude control of combined spacecraft with large parametric uncertainties and adversarial disturbance

This paper investigates the attitude stabilization of combined spacecraft with large parametric uncertainties and adversarial disturbance torque. The adversarial disturbance torque generated by the target spacecraft may vary with time and be far greater than the environmental disturbance torque, posing a substantial challenge to attitude stabilization. To solve this problem, a novel adaptive attitude controller is proposed by incorporating two adaptive laws and a nonlinear disturbance observer (NDO) into the command filtered backstepping approach. The NDO and one adaptive law are employed to estimate and compensate for uncertainties, while the other adaptive law adaptively adjusts the nominal control gain to enhance performance. In comparison to previous works, this proposed controller offers the following advantages: 1) its adaptive nature allows for greater tolerance towards parameter uncertainties; 2) it exhibits higher steady-state accuracy and lower cumulative energy consumption in the presence of large time-varying disturbances. Simulation results validate the effectiveness and performance of the proposed control approach.