Interface Issues in Hardware-In-the-Loop Simulation for Spacecraft On-orbit Docking

This paper presents an idea on the simulation/hardware interface of hardware-in-the-loop (HIL) simulation for spacecraft on-orbit docking. The obstacles that hinder the design of the HIL simulation system are discussed. Then the design criteria of the HIL simulation system are presented based on them. Since the practical HIL simulation system for on-orbit docking is very complicated, the verification about the criteria was done on 1 degree-of-freedom (DOF) case with the nonlinear docking mechanism model. To put the design criteria into practice, the two-degree-of-freedom control structure is required as a control structure for the HIL simulation system for on-orbit docking. The relation ship between the distortion of the HIL simulation and the transfer characteristics of the simulation/hardware interface is qualitatively discussed. The simulation results on 1 DOF case demonstrated that the ideas and the methods discussed above are feasible and practical.