Satellite Docking Simulator Based on Hardware-in-the-loop Hybrid Contact Model

This paper briefly presents a hardware-in-the-loop (HIL) docking simulator concept. A critical requirement for the docking simulation of the HIL simulator is that its 6-degree of freedom (DOF) robots have to mimic the dynamic response of two satellites during contact/docking. However, the closed-loop response is influenced by the time delay of the robots controller, as well as by the robots high structural stiffness. This effects gives rise to unrealistically high impact forces, which not only jeopardize the safety of the facility, but also introduce a nondeterministic error in the docking simulation. Furthermore, the controller time delay will generally destabilize the HIL simulation. In order to mitigate these undesired effects, a new tool for emulating impacts is presented, which is based on a combination of passive and active compliance. This approach ensures safe operation of the simulation facility and also allows to reproduce impact dynamics with different values of stiffness and damping characteristics. This paper presents the extension of the method for more than one dimension. In addition, this paper presents the effect of parameters which are time delay, stiffness, damping and masses of the simulating satellites on the stability of the HIL docking simulator. The method is validated in simulation.