Design And Realization Of Semi-physical Simulation Systems For Satellite Attitude Reconfiguration Control Based On VxWorks

The actuators for satellite attitude control systems are inevitable to be faulty on orbit. It isnecessary to design reconfiguration control methods to keep the attitude of satellite stable in case ofactuator fault. A real-time semi-physical simulation system is also necessary to be built to verify theengineering realizability for the reconfiguration control methods designed. In this paper,reconfiguration control strategies for satellite attitude control system with redundant actuators aredesigned in case of actuator fault. Based on this, a real-time semi-physical simulation system is builtusing a hard-real-time operating system and hardware devices with high reliability. The keycontributions are summarized as follows:As to satellites with four-axis skew reaction wheels, an attitude reconfiguration control methodbased on pseudo-inverse method is designed when the actuators occur to be faulty. As to satellitesequipped with three-axis orthogonal wheels and three-axis magnetorquers, a combined attitudecontrol algorithm during fault mode is introduced. Digital simulation results illustrate the efficiency ofthese two strategies.To verify the engineering realizability for the attitude reconfiguration control methods designed,a real-time semi-physical simulation system for satellite attitude control system(SACS) is developed.The system includes a control computer and a simulation computer using PC104embedded computerloaded with VxWorks real-time operating system, it also includes reaction wheels and otherhardwares in the loop.A remote software is developed using VS2005and STK(Satellite ToolKits).The semi-physical simulation system has the ability to analyze and simulate for satellitedynamics, it can simulate SACS in a high level, and verify the strategies proposed for SACS underactuator faults.The semi-physical simulation result indicates that the attitude reconfiguration control methodsproposed in this paper can make the attitude of satellites stable in case of reaction wheel fault. And italso shows that the semi-physical simulation system developed is of hard-real-time, high reliability,and it is used easily to validate efficiency of the proposed reconfiguration control algorithms.