Hardware-In-the Loop Simulation System Construction for Spacecraft On-orbit Docking Dynamics, Ideas, Procedural and Validation

The Hardware-In-the-Loop (HIL) simulation system for on-orbit docking dynamics is a large-scale complex test equipment. It establishes working conditions for the docking mechanism similar with those on orbit. The kernel of above dynamics HIL simulation system is a mechanical force and movement actions simulator. Besides the mechanical force and movement actions simulator, it also includes an environmental simulator, a microgravity simulator and so on. In a narrow mind, the HIL simulation system for on-orbit docking dynamics refers to the mechanical force and movement action simulator. It is a feedback system which consists of the dynamics simulation model and real-time simulaton computer, the hardwares under test, the force and torque sensor, the motion simulator. The research topic of this paper is limited in above narrow mind. The HIL simulation system for on-orbit docking dynamics is a key technology that played important roles in the lunar excursion of America and in the assembling and re-supplying of Russian MIR space station. Morden space programme enhance the requirements to the HIL simulation for spacecraft docking dynamics. International Space Station (ISS) program also required that the ISS Common Berthing Mechanism (CBM) testing on ground simulator should be performed under operational vacuum and thermal conditions (Office of NRBMP, 1999). In the early days, the physical simulators played main roles in docking dyniamics tests. Because of the development of computor and the complexity of modern docking mechanism, the HIL simulation technology is applied in the docking dynamics simulation. The dynamic docking test system (DDTS) is setup in US (Gates & Graves, 1974), and the integated testing system for docking mechanism was built in former Soviet (Peng et al., 1992). In1980s, docking dynamic test facility (DDTF) was created for testing the handleslatch docking mechanism (Crimbert & Marchal, 1987). National space development agency of Japan built the rendezvous and docking operation test system (RDOTS) testing threepoints handles-latch docking mechanism (Lange & Martin, 2002). The HIL simulation for spacecraft on-orbit docking is a attractive and promising research field. Lim et al. (1989) modeled and simulated the Stewart platform of DDTS. They pointed