Control design for space applications

Spacecraft operation requires a crucial and robust control scheme to accomplish their missions. Hence, sliding mode control (SMC) is one of the robust control approaches capable of fulfilling the spacecraft control operation requirements. Classical SMC, however, produces chattering in the control inputs, which can cause wear and tear in the moving mechanical parts, for instance, actuator. Thus, many researchers introduced modifications in the SMC to attenuate the chattering drawbacks. SMC control development can be divided into two groups; low-order sliding mode control (LOSMC) and high-order sliding mode control (HOSMC). In details, HOSMC requires a sophisticated control algorithm compared to the LOSMC but with a more significant dynamics response. Thus, a new LOSMC is required, producing similar results as HOSMC but less complexity in the control algorithm. Several selected SMC approaches are evaluated on the spacecraft's attitude and orbit control subsystem (ACS) applications; spacecraft attitude and orientation model (SAOM) and spacecraft rendezvous and docking manoeuvres (SRDM). This analysis is a vital medium for evaluating the existing SMC techniques, strengths, and weaknesses for a new LOSMC control development. First, the proposed LOSMC is analysed on the SAOM and SRDM, where the outcomes are compared to the HOSMC. Then, an optimisation technique (particle swarm optimisation (PSO)) is implemented on the new LOSMC and HOSMC. The PSO helps the SAOM and SRDM improving the transient trajectory. The new LOSMC is designed and can perform as the HOSMC with a low complexity algorithm. Finally, this will provide helpful SMC information of the SMC control strategies with their performances on the SAOM and SRDM.