Hybrid non-fragile attitude takeover control of modular spacecraft with communication delay

The modular design pattern revolutionizes the monolithic morphology of traditional spacecraft into the reconfigurable combination of modular units. However, due to the morphological changes, the effective takeover control of the combination through multiple independent modules, including the controller and actuator modules, remains a challenge. In this paper, a robust takeover control scheme with high allocation accuracy, independent of precise inertia, is proposed for the reconfigurable combination in the presence of the inertia uncertainty, model parameters uncertainty, communication delay, and external disturbance. By reregulating the conditions for performance synthesis into a symmetric form with similar structure, a hybrid non-fragile H₂/H_∞ controller is designed for handling two types of controller gain perturbations, achieving superior performance with less energy consumption through simultaneous perturbation suppression. Moreover, through temporarily storing the allocation signals in the initial stage to cover the upper bound of the communication delay, the proposed distributed dynamic allocation scheme enables the actuator modules to implement the control signals jointly to stabilize the combination. Distinguished from general allocators, the proposed high-precision allocation scheme under communication delay can not only ensure full exploitation of controller performance, but also dynamically adjust allocation coefficients based on energy consumption index of controller modules to prevent actuator saturation. Numerical simulations demonstrate the superiority of the proposed hybrid non-fragile controller and the allocation scheme.